Terrorism refers to planned or completed violence intended to cause civilian casualties or degradation of the facilities of civil society, committed to create an atmosphere of fear in order to obtain a political objective. The act may be intended to cause direct casualties, or to disrupt critical infrastructure.
While there is no single definition in international law, a United Nations-sponsored working definitions include one drafted for the Policy Working Group on the United Nations and Terrorism. Reporting to the Secretary-General in 2002, the Working Group stated the following:
Without attempting a comprehensive definition of terrorism, it would be useful to
delineate some broad characteristics of the phenomenon. Terrorism is, in most cases, essentially a political act. It is meant to inflict dramatic and deadly injury on civilians and to create an atmosphere of fear, generally for a political or ideological (whether secular or religious) purpose. Terrorism is a criminal act, but it is more than mere criminality. To overcome the problem of terrorism it is necessary to understand its political nature as well as its basic criminality and psychology. The United Nations
needs to address both sides of this equation.”
Not all insurgency meets the definition of terrorism, as in a "bloodless coup", and not all terrorism is practiced by states or pseudo-states. Some acts against civilians, such as the 1995 Oklahoma City bombing, were carried out by self-radicalized individuals or by small groups having no claim of quasi-state status. Not all suicide attacks are terroristic; the Japanese kamikaze were conducted by uniformed military personnel, in a national chain of command, exclusively attacking military targets.
Simply because the attack is principally against a military target, however, does not automatically exclude it from being considered terroristic. While the Pentagon Building is an iconic military target, the taking of a civilian aircraft and killing civilian passengers and crew does not qualify as a legitimate act of war — distinguishing from the killing of civilian employees of a military organization. Some attacks against military targets are difficult to categorize. The Irgun warned of their attack on the King David Hotel in British Palestine; evacuation would have prevented casualties, although evacuating whenever threatened achieves a political goal. The 1996 Khobar Towers bombing clearly was intended to cause casualties, and most consider it terrorism. Deliberate use of painful methods to kill clearly go over the line, although the actor may consider it a valid psychological technique.
Methods of terrorism include bomb scares and bombings, hijackings, assassinations, kidnappings, cyber-attacks, and attacks using biological, chemical, radiological or nuclear weapons. Nontraditional weapons, sometimes called "nonkinetic", which could be used include damage to critical computer systems or to national infrastructure (e.g., electrical power). Terrorism is a tactic, not a strategy or ideology.
Unquestionably, it can be hard to define.
"Above the gates of hell is the warning that all that enter should abandon hope. Less dire, but to the same effect, is the warning given to those who try to define terrorism." quoted by Lord Carlisle in a report to the UK Parliament 
Nevertheless, there is also a tendency among some politicians to apply "terrorist" as a label to things that, in a less charged environment, would be considered simple criminal acts. British security authorities sometimes ironically use the term "ordinary decent criminal" to refer to people with no ideological motivations; there is also concern about redefining legitimate dissent as terrorism.
Francis Fukuyama wrote
The term “war on terrorism” is a misnomer, resulting in distorted ideas of the main threat facing Americans today. Terrorism is only a means to an end; in this respect, a “war on terror” makes no more sense than a war on submarines.
While "war on terror" does lack precision, the "internationalization of terror", or cooperation among different groups, not necessarily sharing an ideology, is a reality. Hoffman argues that the first classic example was the hijacking of an Israeli national airliner in July 1968, arguing that it was specifically intended to create international pressure. Probably a better example, however, was the "subcontracting" of an attack in Israel to the Japanese Red Army by the Popular Front for the Liberation of Palestine; the PFLP gave sanctuary in Lebanon to the JRA, in what was essentially a marriage of convenience. 
Terrorism has many definitions and the concept is the subject of much controversy. The word terrorism was first used in the late 1790s by opponents of the French Revolution.
What terrorism is not
In the context of the French Revolution, the Terror was the period of revolutionary history from June 1793 through July 1794, during which the Jacobins, led by Maximilian Robespierre, eliminated many of their opponents among the French political elite and society, from aristocrats to peasants, through execution by guillotine.  For Robespierre, "Terror" meant simply "prompt, severe, inflexible justice"; and was "a consequence of the general principle of democracy applied to the most pressing needs of the fatherland." (Address, National Convention, 1794). However, the terrorism of the French Revolution is not what is now generally meant by "terrorism".
The three main reasons for the Terror were the strength of the counterrevolutionary forces, the lack of a parliamentary tradition in France that would have enabled the formation of stable political parties and tolerance for opposing views, and, most important, the war with foreign powers that began in April 1792.
Russian revolutionary terrorism in the late nineteenth century was another antecedent that the present-day use of the term does not characterize. These revolutionary terrorists believed incorrectly that it would be possible to overthrow the Tsarist form of government by assassinating high officials in the regime. The simplicity of such a view, as it appears to us today, is only a reflection of the lack of development of advanced social theory at the time. It did not seem unreasonable in a time and place where the head of state, the Tsar, wielded such absolute power and so completely dominated the political landscape. A signal difference between these terrorists and those of today is that the former specifically targeted those individuals whom they believed responsible for social ills, poor governance, and injustice. In a famous incident in 1905, a socialist revolutionary refused to throw a bomb at the carriage of the Tsar's uncle, the Grand Duke Sergei, when he realized that the carriage also contained the Grand Duke's children, who were not guilty of any crime in the eyes of the terrorists. Albert Camus used this incident as the basis for his play Les Justes (usually translated as The Just Assassins, but more accurately The Just Ones). Also, these revolutionaries called themselves terrorists, giving this noun the particular moral quality exemplified in that 1905 incident. By contrast, the terrorists of today decline this label that is instead applied to them by others, and they do not as a rule in their actions distinguish between individuals who are "guilty" of specific political crimes and those who are not: for them, it suffices to be a member of a social category or simply to be in the wrong place at the wrong time.
Modern definitions of terror
The common elements of terrorism , are “the use of, or threat to use, violence”; “the goal is to attain political objectives”; and “the targets of terrorism are civilians”. While there is not a single definition in international law, the most widely accepted legal definition, in the U.S., is in Title 22 of the U.S. Code, Section 2656f(d), which states: "The term ‘terrorism’ means premeditated, politically motivated violence perpetrated against non-combatant targets by sub-national groups or clandestine agents, usually intended to influence an audience."
Often the definition of terrorism varies among the various agencies of a country's government, an example of this is in the USA:
|Department of Defense||The calculated use of unlawful violence to inculcate fear, intended to coerce or to intimidate governments or societies in the pursuit of goals that are generally political, religious, or ideological. |
|FBI||The unlawful use of force and violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives |
|State Department||Premeditated, politically motivated violence perpetrated against noncombatant targets by subnational groups or clandestine agents, usually intended to influence an audience. “For purposes of this definition, the term “noncombatant” is interpreted to include, in addition to civilians, military personnel who at the time of the incident are unarmed and/or not on duty.” |
A very different definition, far broader than generally accepted, was presented at the International Conference on Terrorism of the Organization of the Islamic Conference in 1987. It makes significant differentiations based on the motivations of the actor, as opposed to targets or effects. It is, however, not unprecedented among people who feel dominated by the West.
Terrorism is an act carried out to achieve an inhuman and corrupt objective, and involving threat to security of any kind, and violation of rights acknowledged by religion and mankind. . The given definition, according to its author, excludes:
acts of national resistance exercised against occupying forces, colonizers and usurpers; resistance of peoples against cliques imposed on them by the force of arms; rejection of dictatorships and other forms of despotism and efforts to undermine their institutions; resistance against racial discrimination and attacks on the latter's strongholds; retaliation against any aggression if there is no other alternative.
but includes: acts of piracy on land, air and sea; all colonialist operations including wars and military expeditions; all dictatorial acts against peoples and all forms of protection of dictatorships; all military methods contrary to human practice, such as the use of chemical weapons, the shelling of civilian populated areas, the blowing up of homes, the displacement of civilians, etc.; all types of pollution of geographical, cultural and informational environment. Indeed, intellectual terrorism may be one of the most dangerous types of terrorism; all moves that undermine adversely affect the condition of international or national economy, adversely affect the condition of the poor and the deprived, deepen up nations with the shackles of socio-economic gaps, and chain up nations with the shackles of exorbitant debts; all conspiratorial acts aimed at crushing the determination of nations for liberation and independence, and imposing disgraceful pacts on them.
State Sponsorship of Terrorism
There are basically three categories of state sponsorship of terrorism:
1. States supporting terrorism – “states that support terrorist organizations, providing financial aid, ideological support, military or operational assistance” 
2. States operating terrorism – “states that initiate, direct and perform terrorist activities through groups outside their own institutions”
3. States perpetrating terrorism – “states perpetrating terrorist acts abroad through their own official bodies” or perpetrating terrorist acts domestically (i.e. within its own borders).
Throughout the 20th century, groups that engaged in terrorist activities were sponsored directly or indirectly by governments in furtherance of their political and economic aims. The Cuban Communist government of Fidel Castro was a notable supporter of insurgent groups in South America and Africa, often acting as a proxy for the Soviet Union. China under Mao Zedong funded groups, including the Khmer Rouge in Cambodia. The Government of South Africa, when under its policy of apartheid, sponsored rebel terrorist groups in neighboring Angola and Mozambique to destabilise their regimes.
Under president Jimmy Carter, the USA sponsored the mujahideen in Afghanistan, including the Taliban, in their insurgent campaign against the Soviet-backed government of President Najibullah. The Taliban, the most extreme fundamentalist group among the mujahideen, eventually took over Afghanistan, with widespread massacres of Hazaras, a mostly Shi'a ethnic group  Under President Ronald Reagan, the USA covertly funded the Contras, various armed guerrilla groups that opposed Nicaragua's Frente Sandinista de Liberacion Nacional, the Sandinista Junta that ruled Nicaragua following the July 1979 overthrow of President Anastasio Somoza Debayle. Not ony the Sandinista government, but also groups such as [Amnesty International], Americas Watch and Witness for Peace frequently accused the Contras of indiscriminate attacks on civilians. Libya in the 1970's covertly funded the Provisional Irish Republican Army.
Characteristics of Terrorist attacks
Planning and organization
Terrorist attacks are planned to ensure the largest amount of publicity to spread their cause to the general population. An example is the 1998 bombings of U.S. Embassies in Africa, which took al-Qaeda nearly five years to plan, to carry out near-simultaneous attacks in Kenya and Tanzania.
When planning a major attack, the terrorists gather intelligence on the intended target such as its defenses and vulnerabilities. Logistics specialists assemble the weapons, communications equipment, and arrange transportation and escape routes for the team that will carry out the attack. Once all the preparations are complete, the terrorist team will execute the plan. Usually separate teams carry out each step for security reasons so if one team is captured, they can't tell about the other team.
Terrorist groups usually keep their plans secret, operating underground and away from the public and government authorities. Terrorists are often organized in a clandestine cell system, where the individuals may only know the members of their own cell, but are part of a larger terrorist network and several cells can work together to plan a terrorist attack. This means that if members of one cell are captured, the entire network will not be discovered.
The main targets of terrorism are civilians, because they are easy to attack and these attacks create an atmosphere of fear, leading to political discontent. Attacks on buildings may be symbolic and psychological, or indeed attempts to cause large-scale death and destruction. Other terrorist attacks aim at business executives and corporate offices; water supply and pipelines; power facilities such as power plants, dams and power grids; and transportation facilities such as airplanes and airports, subways, trains and train stations, and buses and bus terminals. Attacks against military bases, if they minimize uninvolved civilian casualties, are not always considered terrorism.
Terrorist weapons range from the knife to weapons of mass destruction.
Bombing is a common terrorist tactic because of its simplicity and lack of the need of skill to create, plant, and detonate a crude bomb. Bombs also offer the opportunity to escape the immediate area of the attack if not used as a suicide attack. Assassination, kidnapping, and assaults against well-defended targets require more sophisticated organization, planning, and weaponry.
Weapons of mass destruction
Weapons of mass destruction include biological, chemical, nuclear and radiological weapons. The use of such weapons, against a civilian population for political goals, is especially frightening, but also, to date, has been less practical than some have been suggested. There have been few known attacks, with relatively light casualties compared with the expectations of use by a professional military.
Bioterrorism would be the use of a biological weapon as a method of terrorism. Since biological warfare lends itself to clandestine deployment, and only nuclear weapons can cause comparably massive casualties with relatively small weights of material, it is most feared. The major chemical and biological attacks came from Aum Shinrikyo (Supreme Truth) in Japan.
Aum Shinrikyo is a Japanese cult founded in 1984 by Shoko Asahara, who initially preached meditation and non violence. Asahara decided that Aum should field candidates for the 1990 Japanese parliamentary elections. However, when none of its candidates were elected, Asahara accused the Japanese government of rigging the elections. Around this time that he started justifying murder on spiritual grounds, in a doctrine called 'poa', and he began to preach to his followers about an approaching nuclear apocalypse, a war between Japan and the U.S., and the group prepared to commit terrorist attacks to hasten that Apocalypse. It is the only organization to have made serious attempts at terrorism using weapons of mass destruction, although its use of a biological weapon was completely ineffective, and its use of chemical weapons was far less devastating than a more competently delivered attack.
Asahara and other leaders of the sect were arrested, tried and found guilty. After Asahara’s imprisonment, Fumihiro Joyu became the new head of the organization. Aum changed its name to Aleph in 2000, forbid the use of poa, apologized for its past acts of terrorism and paid reparation to the victims of the Tokyo sarin attack.
Perhaps more accurate than the popular term cyberterrorism is electronic attack, which encompasses the use of computing and electronic techniques not only against Internet-related systems, but also telecommunications networks, System Control And Data Acquisition for critical infrastructure, electrical power, etc.
Early examples of terrorism were the actions of the Jewish Zealots. Known to the Romans as sicarii or dagger-men, the Zealots engaged in violent attacks on Roman occupation forces and fellow Hebrews who were accused of collaboration with the Romans. The next group to show characteristics of terrorism were the Assassins. The Assassins were a breakaway faction of Shia Islam called Nizari Ismalis who used the tactic of assassination of enemy leaders. The tactics used by the Assassins involved sending a lone man to kill an enemy leader at the cost of his own life, instilling fear in the enemy.
During Reconstruction after the American Civil War the Ku Klux Klan was formed by defiant Southerners waged a campaign of violence and intimidation against freed former slaves and supporters of Reconstruction. However, Communism was just beginning as an ideological basis for revolution, and the 20th century would bring about many new developments in terrorism in support of political aims.
Sometimes, a terrorist campaign mixes nationalism and Islamism.
Anarchism and Individual Anger
In the late 19th century, small groups of revolutionary anarchists were formed. These anarchists assassinated heads of state from Russia, France, Spain, Italy, and the USA. But their lack of organization and refusal to cooperate with other social movements made anarchism ineffective as a political movement.
The 1995 Oklahoma City bombing, when 168 people were killed and another 800 injured, was carried out by individuals angry with the government, but having no clear political goal.
The Growth of Nationalism
Nationalism intensified around the world during the early 20th century and it became a powerful force in the various peoples of colonial empires.
The Black Hand was a group active before World War I that was involved in the assassination of Franz Ferdinand, Archduke of Austria which was considered an act of terrorism that started the First World War. 
Algerians, seeking independence from France, fought a war making extensive use of urban terrorism as well as guerrilla warfare. French counterinsurgency was unquestionably brutal as well, using, in part, the torture doctrine of Roger Trinquier, one of the relatively few Western theoreticians to argue its use. The Front de libération nationale (FLN) independence movement killed random French civilians and foreign visitors as part of its overall strategy. Perhaps the first example of a modern terrorist movement was Algeria's Front de libération nationale (FLN) which killed random French civilians in a campaign to win independence for Algeria from colonial rule by France.
A tactical message from the FLN was that terrorist attacks on civilians, by promoting public outrage could lead to vicious counter-terrorism, that would bring increasing number of recruits to the insurgency cause, leading, after a cycle of increasing violence and destruction, to eventual victory.
Currently amongst the most active terrorist groups are Islamic fundamentalist groups linked to insurgents seeking the independence of Chechnya from Russia. Chechen separatists have deliberately attacked civilian targets; in 2004 an attack on a school in North Ossetia left 300 dead, mostly children, and in 2002, Chechen commandos attacked a theater in Moscow taking 700 civilians hostage. But not all Chechen insurgents are terrorists, and Western governments, including the USA, have said that Russia has tried to portray all Chechens as Islamist terrorists in order to justify the harsh measures used to try to crush Chechen resistance. The US State Department has criticised the Russian government, saying that “the lack of a political solution and the number of credible reports of massive human rights violations, we believe, contribute to an environment that is favorable toward terrorism.”
In Ireland, the Provisional Irish Republican Army (IRA) was founded to try to end Northern Ireland's status as part of the United Kingdom, and to establish a single united all-Ireland socialist state by armed force. The organisation was made illegal in both the UK and in the Republic of Ireland, but was extensively financed by sympathisers in the USA . The Provisional IRA's strategy during The Troubles, as they were known, was to use violence to cause the collapse of the Northern Ireland administration, and to cause so many casualties among the British security forces that British public opinion would force the government to withdraw those forces, against the will of the majority Unionist community in Northern Ireland. Initially a small group with little support even among the nationalist Irish community, the Provisional IRA benefited hugely from the decision of the British government in 1971 to introduce internment in Northern Ireland. Internment - detention of terrorist suspects without trial, was a response of the Government to intimidation of witnesses in court proceedings, but the internment camps, in which large numbers of suspects were held indefinitely, became training and indoctrination camps for the inmates, and the lack of legal process provoked widespread discontent amongst the Nationalist community, and lost the British Government the "moral high ground"  Between 1971 and 1994, the armed campaign mainly targeted the British Army, the Royal Ulster Constabulary, the Ulster Defence Regiment, and economic targets in Northern Ireland, but it also included sectarian killings such as the Kingsmill massacre of 1976.
The IRA also took its campaign to England, including planting bombs in pubs in Birmingham, Guildford, Warrington, Brighton, London's docklands and elsewhere, and they targeted British government officials, politicians, judges, and police officers. The armed campaign ended in 2005, allowing the political wing of the Republican movement, Sinn Féin, to enter into a power-sharing agreement with the Unionist political parties. During the campaign, it is estimated that the provisional IRA were responsible for about 1,800 deaths including 1,100 members of the security forces and about 600 civilians. While the Provisional IRA has disarmed, splinter groups such as the Real IRA and Continuity IRA remain a threat.
In the years surrounding the formation of the modern state of Israel, Jewish paramilitary groups used terrorist tactics both to expel the British authorities (who then ruled Palestine) and to drive the Arab civilian population from their homes and villages in an attempt to create a territory within which Jewish settlers would be the majority. Prominent among these groups was the Irgun Zvai Leumi (IZL). In February 1944, Menachim Begin, then a commander of the IZL, announced the start of an underground campaign against the British authorities., a campaign that included bombing the King David Hotel in Jerusalem, which killed 91 people.  After Israel achieved independence, Begin entered the political mainstream; he was to become its sixth Prime Minister, and a recipient of the Nobel Peace Prize.
The Irgun campaign involved conquest and occupation of territory then occupied by Arabs. One typical target was the small Arab settlement of Deier Yassin. In April 1948, Irgun fighters entered the village to expel the inhabitants, and, when they met some resistance, killed a large number of the villagers (exactly how many is disputed). This event, the so-called "Massacre of Deier Yassin", greatly added to the fear of the Palestinians, leading them to flee their homes and villages in increasing numbers, so accomplishing Irgun's objectives. In the process a large population of Palestinian Arab were made refugees, and indeed became "stateless".
In Sri Lanka, The Liberation Tigers of Tamil Eelam (the "Tamil Tigers") is a separatist group that seeks an independent state in areas of Sri Lanka that are inhabited by ethnic Tamils. The Tamil Tigers have used conventional, guerrilla, and terror tactics, including 200 suicide bombings, in a civil war that has claimed more than 60,000 lives and displaced hundreds of thousands of Sri Lankans since 1983; a ceasefire was negotiated in 2002, but fighting resumed in 2006. Notable victims of terrorist action include Rajiv Gandhi, Prime Minister of India, who was assassinated by Tamil Tigers in 1991, and Sri Lankan president Premadasa, who was assassinated in 1993 
After World War I terrorism became an official policy in states such as Nazi Germany and the Soviet Union. Adolf Hitler and Joseph Stalin, the leaders of these states, used arrest, torture, imprisonment, and execution to bring fear to the people of the country so they would not question their actions.
In the refugee camps, anger and resentment, in continuing conditions of poverty and insecurity, provided the seeds for a resistance movement that itself turned to terror as a tactic. Yasser Arafat's Palestine Liberation Organization (PLO) committed many dramatic acts of terrorism, including the massacre of 11 Israeli athletes during the 1972 Munich Olympics. But since the PLO's goals were political, rather than religious, Arafat distanced himself from terrorism. Hamas and Hezbollah, while operating across national borders, still were primarily concerned with the Israel-Palestine Conflict.
However, while the PLO itself turned from violence towards conventional political activity, other groups, particularly extremist groups of Islamic fundamentalists became active in a Salafist movement, called a fourth wave of Islamic terrorism. In addition to Salafist efforts to expel corrupt Muslim rulers, eject the west from traditional Muslim lands, and restore the Caliphate, terrorism also was used as a tactic in Islamic sectarian conflict, especially in the Iraq War after major combat. While a-Qaeda certainly is Islamist as discussed in Michael Scheuer's analysis of Abu Jandal,  it is not as Salafist as the Taliban. Indeed, Abu Jandal himself spoke of takfir groups as far more extreme than bin Laden.
On 27th December 2007, Benazir Bhutto, the former Prime Minister of Pakistan and leader of the Pakistan People’s Party, was assassinated in Rawalpindi by a suicide bomber as she was leaving an election rally. At least 20 other people died in the attack. This event followed a series of similar attacks on security and government officials, and it was the second suicide attack against her in the run-up to elections, scheduled for January 2008. She had returned to Pakistan in October 2007 after years of self-imposed exile; on the day of her arrival, she led a motor cavalcade through the city of Karachi that was hit by a double suicide attack that left 138 dead. It is thought that militant Islamic groups are responsible for these terrorist attacks. Benazir Bhutto herself, claimed that, before the first attack, she had passed intelligence details on to ruling General Musharraf, about four suicide squads roaming Karachi. She claimed that they came from the Pakistani Taliban, the Afghan Taliban, al-Qaeda and "a fourth group from Karachi". 
- See also: 2005 London bombings
Attacks in and against North America
- See also: 1983 bombing of the U.S. embassy in Beirut
- See also: 1983 Beirut barracks bombings
- See also: 1993 World Trade Center bombing
- See also: 1998 bombings of U.S. Embassies in Africa
- See also: 9-11 attack
Major terrorist attacks have been taking place on U.S. soil, or against U.S. diplomatic installations, since the 1980s. Some attacks, such as the bombing of the USS Cole or the 1996 Khobar Towers bombing were against purely military targets by non-national attacks; these do not constitute terrorism under all definitions.
The 1993 World Trade Center bombing was conducted by non-national radical Islamists, as was the 9-11 attack. Al-Qaeda clearly conducted the 2001 attack, but probably did not, as an organization, conduct the 1993 attack. The latter, however, did involve Ramzi Yousef, nephew of Khalid Sheikh Mohammed, who personally was engaging in terrorism but had not yet joined al-Qaeda. Transnational terrorism does not often follow strict organizational charts.
A number of transnational terror attacks have been stopped in the planning phase, or even in the attempt (e.g., overpowering "shoe bomber" Richard Reid before he could detonate his bomb).
- See also: Baader-Meinhof Gang
- See also: Red Brigades
- See also: 2004 Madrid bombings
- See also: Irish Republican Army
Right-wing ideological terrorism
In 1995, the Oklahoma City bombing was carried out by individuals with domestic right-wing anti-government positions, although they had vague political goals; some of their anger was against what they considered state terror against the Branch Davidians at Waco, Texas in 1993. Assassinations of abortion providers, the bombing of the Atlanta Olympics and of abortion clinics, were carried out by U.S. citizens with a clearer if illegal agenda.
Terrorist claims and statements
It is often said, especially by critics of the West and of capitalism, that terrorism is merely a label ascribed by those in power to those who do not accept their authority, and resist it with violent and unlawful means. On this view, whether someone is better described as a "terrorist" or instead as a "freedom-fighter" depends on whether the state's power is thought to be wielded lawfully and fairly. For example, the African National Congress (ANC) was characterised as a terrorist organisation by the apartheid South African government (and by the governments of the UK and USA), but strongly rejected that description. However, in 1963 Nelson Mandela, the leader of the military wing of the ANC Umkhonto we Sizwe ("Spear of the Nation"), was sentenced to life imprisonment on terrorism charges. Mandela, at his trial, openly declared his involvement in planning sabotage:
"I do not deny that I planned sabotage. I planned it as a result of a calm and sober assessment of the political situation." Nelson Mandela, at his trial for terrorism in South Africa, 1963
The policy of the ANC at the time was to attack military and government targets and to sabotage economic targets, and not to directly target civilians . However civilians were occasionally victims of these actions; for example, in 1983, a car bomb in Pretoria outside the headquarters of the South African air force killed 16 people.  The ANC was legalised in 1990 and renounced violence; Nelson Mandela was released from prison in 1990, became a recipient of the Nobel Peace Prize in 1993, and was elected president of South Africa in 1994.
In marked contrast to the ANC, some other groups notably al-Qaeda, very deliberately target civilians. Terrorists typically try to justify their actions to nonbelievers as retaliation for perceived wrongs. Thus Osama bin Laden, leader of al-Qaeda, claimed,
"As for their accusations of terrorizing the innocent, the children, and the women, these are in the category of 'accusing others with their own affliction in order to fool the masses.' The evidence overwhelmingly shows America and Israel killing the weaker men, women and children in the Muslim world and elsewhere." Osama bin Laden, in Nida'ul Islam magazine, October-November 1996.
Bin Laden further reached back in time in 2004, claiming,
"God knows it did not cross our minds to attack the towers but after the situation became unbearable and we witnessed the injustice and tyranny of the American-Israeli alliance against our people in Palestine and Lebanon, I thought about it. And the events that affected me directly were that of 1982 and the events that followed -- when America allowed the Israelis to invade Lebanon, helped by the United States Sixth Fleet. As I watched the destroyed towers in Lebanon, it occurred to me punish the unjust the same way (and) to destroy towers in America so it could taste some of what we are tasting and to stop killing our children and women." Usama bin Laden, admitting responsibility for attacks of September 11, 2001, on videotape shown on Al Jazeera, October 29, 2004.
- Secretary General's Policy Working Group on the United Nations and Terrorism (December 2004), "Preface", Focus on Crime and Society 4, (A/57/273-S/2002/875, annex)
- The Definition of Terrorism Report to the UK Parliament, March 2007
- Phase III in the War on Terrorism? Challenges and opportunities, Brookings Institution, 2003-05-14. Retrieved on 2008-06-26.
- Bruce Hoffman (2006), Inside Terrorism (Revised ed.), Columbia University Press, ISBN 023112699, pp. 63-64
- In the Spotlight: Japanese Red Army (JRA), Center for Defense Information, October 9, 2003
- Online Etymology Dictionary - Terrorism
- Dr Marisa Linton, "The Terror in the French Revolution," p. 1, at .
- Ganor B (2002), 3(4) Defining terrorism: Is one man’s terrorist another man’s freedom fighter?, International Institute for Counter-Terrorism, Herzliya
- United States Department of Defense, Office of Joint Chiefs of Staff, Joint Publication 1-02: Department of Defense Dictionary of Military and Associated Terms Washington , DC : United States Department of Defense, 12 April 2001 – As amended through 5 June 2003, p. 531.
- Counterterrorism Threat Assessment and Warning Unit, National Security Division, Federal Bureau of Investigation, Terrorism in the United States 1999: 30 Years of Terrorism – A Special Retrospective Edition (Washington, DC: United States Department of Justice, 1999), p. i.
- Office of the Coordinator for Counterterrorism, Patterns of Global Terrorism 2002 US Department of State Publication 11038 ( Washington , DC : State Department, April 2003), p. 13.
- Towards a Definition of Terrorism, International Conference on Terrorism called by the Organization of the Islamic Conference, reported in Al-Tawhid, June 22-26, 1987
- Massacres of Hazaras in Afghanistan Human Rights Watch
- Aum Shinrikyo MIPT Terrorism knowledge base
- Edgerton, Keith How Did World War I Begin?. History News Network (October 17, 2001)
- Chechnya-based Terrorists Council on Foreign Relations website
- BBC News Rich friends in New York 26 September 2001
- Army 'warned against internment'BBC News 1 January, 2002
- Conflict and Politics in Northern Ireland (1968 to the Present) University of Ulster CAIN project
- The Bombing of the King David Hotel from the Irgun site
- NY Times Op-Ed article written by prominent American Jews (including Albert Einstein) critical of Menahem Begin's visit to the States, Dec. 2, 1948
- Liberation Tigers of Tamil Eelam Council for Foreign Relations
- Fernando Reinares (9 January 2005), Conceptualising International Terrorism, Real Instituto Elcano, Area: International Terrorism - ARI Nº 82/2005 (Translated from Spanish)
- Shaykh Usamah Bin-Muhammad Bin-Ladin; Ayman al-Zawahiri, amir of the Jihad Group in Egypt Abu-Yasir Rifa'i Ahmad Taha, Egyptian Islamic Group; Shaykh Mir Hamzah, secretary of the Jamiat Ulema-e-Pakistan (JUP); Fazlur Rahman, amir of the Jihad Movement in Bangladesh (23 February 1998), Jihad Against Jews and Crusaders; World Islamic Front Statement
- Michael Scheuer (March 28, 2006), "Al-Qaeda Doctrine: Training the Individual Warrior", Terrorism Focus, The Jamestown Foundation
- Peter L. Bergen (2006), The Osama bin Laden I Know: An Oral History of al Qaeda's Leader, Free Press, ISBN 0743278917, pp. 259-260
- Umkhonto we Sizwe (Military wing of the African National Congress): We are at War! Manifesto, December 16, 1961
- Medal of Honor for a terrorist Pittsbugh-Tribune Review, July 27, 2003
- African National Congress MIPT Terrorism Knowledge Base
- 1983: Car bomb in South Africa kills 16 BBC
- al-Qaeda MIPT Terrorism knowledge base