Counterterrorism (alternatively spelled: counter-terrorism), also known as anti-terrorism, relates to the practices, military tactics, techniques, and strategies that governments, law enforcement, businesses, and intelligence agencies use to combat or eliminate terrorism.[1]
If an act of terrorism occurs as part of a broader insurgency (and insurgency is included in the definition of terrorism) then counterterrorism may additionally employ counterinsurgency measures. The United States Armed Forces uses the term "foreign internal defense" for programs that support other countries' attempts to suppress insurgency, lawlessness, or subversion, or to reduce the conditions under which threats to national security may develop.[2] [3] [4]
The first counterterrorism body to be formed was the Special Irish Branch of the Metropolitan Police, later renamed the Special Branch after it expanded its scope beyond its original focus on Fenian terrorism. Various law enforcement agencies established similar units in the United Kingdom and elsewhere.[5] The first tactical counterterrorist unit was GSG 9 of the German Federal Police, formed in response to the 1972 Munich massacre.[6]
Counterterrorist forces expanded with the perceived growing threat of terrorism in the late 20th century. After the September 11 attacks, Western governments made counterterrorism efforts a priority. This included more extensive collaboration with foreign governments, shifting tactics involving red teams,[7] and preventive measures.[8]
Although terrorist attacks affecting Western countries generally receive a disproportionately large share of media attention,[9] most terrorism occurs in less developed countries.[10] Government responses to terrorism, in some cases, tend to lead to substantial unintended consequences,[11] such as what occurred in the above-mentioned Munich massacre.
See also: Intelligence cycle management, Intelligence analysis, HUMINT and Counterintelligence.
Most counterterrorism strategies involve an increase in policing and domestic intelligence gathering. Central techniques include intercepting communications and location tracking. New technology has expanded the range of military and law enforcement options for intelligence gathering. Many countries increasingly employ facial recognition systems in policing.[12] [13]
Domestic intelligence gathering is sometimes directed to specific ethnic or religious groups, which are the sources of political conversy. Mass surveillance of an entire population raises objections on civil liberties grounds. Domestic terrorists, especially lone wolves, are often harder to detect because of their citizenship or legal status and ability to stay under the radar.[14]
To select the effective action when terrorism appears to be more of an isolated event, the appropriate government organizations need to understand the source, motivation, methods of preparation, and tactics of terrorist groups. Good intelligence is at the heart of such preparation, as well as a political and social understanding of any grievances that might be solved. Ideally, one gets information from inside the group, a very difficult challenge for human intelligence operations because operational terrorist cells are often small, with all members known to one another, perhaps even related.[15]
Counterintelligence is a great challenge with the security of cell-based systems, since the ideal, but the nearly impossible, goal is to obtain a clandestine source within the cell. Financial tracking can play a role, as a communications intercept. However, both of these approaches need to be balanced against legitimate expectations of privacy.[16]
See main article: Anti-terrorism legislation.
In response to the growing legislation.
Since 1978 the UK's terrorism laws have been regularly reviewed by a security-cleared Independent Reviewer of Terrorism Legislation, whose often influential reports are submitted to Parliament and published in full.
One of the primary difficulties of implementing effective counterterrorist measures is the waning of civil liberties and individual privacy that such measures often entail, both for citizens of, and for those detained by states attempting to combat terror.[23] At times, measures designed to tighten security have been seen as abuses of power or even violations of human rights.[24]
Examples of these problems can include prolonged, incommunicado detention without judicial review or long periods of 'preventive detention';[25] risk of subjecting to torture during the transfer, return and extradition of people between or within countries; and the adoption of security measures that restrain the rights or freedoms of citizens and breach principles of non-discrimination. Examples include:
Many argue that such violations of rights could exacerbate rather than counter the terrorist threat. Human rights activists argue for the crucial role of human rights protection as an intrinsic part to fight against terrorism.[27] This suggests, as proponents of human security have long argued, that respecting human rights may indeed help us to incur security. Amnesty International included a section on confronting terrorism in the recommendations in the Madrid Agenda arising from the Madrid Summit on Democracy and Terrorism (Madrid March 8–11, 2005):
While international efforts to combat terrorism have focused on the need to enhance cooperation between states, proponents of human rights (as well as human security) have suggested that more effort needs to be given to the effective inclusion of human rights protection as a crucial element in that cooperation. They argue that international human rights obligations do not stop at borders, and a failure to respect human rights in one state may undermine its effectiveness in the global effort to cooperate to combat terrorism.[28]
Some countries see preemptive attacks as a legitimate strategy. This includes capturing, killing, or disabling suspected terrorists before they can mount an attack. Israel, the United Kingdom, the United States, and Russia have taken this approach, while Western European states generally do not.
Another major method of preemptive neutralization is the interrogation of known or suspected terrorists to obtain information about specific plots, targets, the identity of other terrorists, whether or not the interrogation subjects himself is guilty of terrorist involvement. Sometimes more extreme methods are used to increase suggestibility, such as sleep deprivation or drugs. Such methods may lead captives to offer false information in an attempt to stop the treatment, or due to the confusion caused by it. In 1978 the European Court of Human Rights ruled in the Ireland v. United Kingdom case that such methods amounted to a practice of inhuman and degrading treatment, and that such practices were in breach of the European Convention on Human Rights Article 3 (art. 3).
The human security paradigm outlines a non-military approach that aims to address the enduring underlying inequalities which fuel terrorist activity. Causal factors need to be delineated and measures implemented which allow equal access to resources and sustainability for all people. Such activities empower citizens, providing "freedom from fear" and "freedom from want".
This can take many forms, including the provision of clean drinking water, education, vaccination programs, provision of food and shelter and protection from violence, military or otherwise. Successful human security campaigns have been characterized by the participation of a diverse group of actors, including governments, NGOs, and citizens.
Foreign internal defense programs provide outside expert assistance to a threatened government. FID can involve both non-military and military aspects of counterterrorism.
A 2017 study found that "governance and civil society aid is effective in dampening domestic terrorism, but this effect is only present if the recipient country is not experiencing a civil conflict."[29]
Terrorism has often been used to justify military intervention in countries where terrorists are said to be based. Similar justifications were used for the U.S. invasion of Afghanistan and the second Russian invasion of Chechnya.
Military intervention has not always been successful in stopping or preventing future terrorism, such as during the Malayan Emergency, the Mau Mau uprising, and most of the campaigns against the IRA during the Irish Civil War, the S-Plan, the Border Campaign, and the Troubles in Northern Ireland. Although military action can temporarily disrupt a terrorist group's operations temporarily, it sometimes does not end the threat completely.[30]
Repression by the military in itself usually leads to short term victories, but tend to be unsuccessful in the long run (e.g., the French doctrine used in colonial Indochina and Algeria[31]), particularly if it is not accompanied by other measures. However, new methods such as those taken in Iraq have yet to be seen as beneficial or ineffectual.[32]
Whatever the target of terrorists, there are multiple ways of hardening the targets to prevent the terrorists from hitting their mark, or reducing the damage of attacks. One method is to place hostile vehicle mitigation to enforce protective standoff distance outside tall or politically sensitive buildings to prevent car bombings. Another way to reduce the impact of attacks is to design buildings for rapid evacuation.[33]
Aircraft cockpits are kept locked during flights and have reinforced doors, which only the pilots in the cabin are capable of opening. UK railway stations removed their garbage bins in response to the Provisional IRA threat, as convenient locations for depositing bombs. Scottish stations removed theirs after the 7 July 2005 London Bombings as a precautionary measure. The Massachusetts Bay Transportation Authority purchased bomb-resistant barriers after the September 11 attacks.
Due to frequent shelling of Israel's cities, towns, and settlements by artillery rockets from the Gaza Strip (mainly by Hamas, but also by other Palestinian factions) and Lebanon (mainly by Hezbollah), Israel has developed several defensive measures against artillery, rockets, and missiles. These include building a bomb shelter in every building and school, but also deploying active protection systems such as the Arrow ABM, Iron Dome and David's Sling, which intercept the incoming threat in the air. Iron Dome has successfully intercepted hundreds of Qassam rockets and Grad rockets fired by Palestinians from the Gaza Strip.[34] [35]
A more sophisticated target-hardening approach must consider industrial and other critical industrial infrastructure that could be attacked. Terrorists do not need to import chemical weapons if they can cause a major industrial accident such as the Bhopal disaster or the Halifax Explosion. Industrial chemicals in manufacturing, shipping, and storage thus require greater protection, and some efforts are in progress.[36]
Equipping likely targets with containers of pig lard has been used to discourage attacks by suicide bombers. The technique was apparently used on a limited scale by British authorities in the 1940s. The approach stems from the idea that Muslims perpetrating the attack would not want to be "soiled" by the lard in the moment before dying.[37] The idea has been suggested more recently as a deterrent to suicide bombings in Israel.[38] However, the actual effectiveness of this tactic is likely limited. A sympathetic Islamic scholar could issue a fatwa proclaiming that a suicide bomber would not be polluted by the swine products.
For a threatened or completed terrorist attack, an Incident Command System (ICS) may be invoked to control the various services that may need to be involved in the response. ICS has varied levels of escalation, such as might be required for multiple incidents in a given area (e.g. 2005 London bombings or the 2004 Madrid train bombings), or all the way to a National Response Plan invocation if national-level resources are needed. For example, a national response might be required for a nuclear, biological, radiological, or significant chemical attack.
Fire departments, perhaps supplemented by public works agencies, utility providers, and heavy construction contractors, are most apt to deal with the physical consequences of an attack.
Again under an incident command model, local police can isolate the incident area, reducing confusion, and specialized police units can conduct tactical operations against terrorists, often using specialized counterterrorist tactical units. Bringing in such units will typically involve civil or military authority beyond the local level.
Emergency medical services are capable of triaging, treating, and transporting the more severely affected individuals to hospitals, which typically have mass casualty and triage plans in place for terrorist attacks.
Public health agencies, from local to the national level, may be designated to deal with identification, and sometimes mitigation, of possible biological attacks, and sometimes chemical or radiologic contamination.
Many countries have dedicated counterterrorist units trained to handle terrorist threats. Besides various security agencies, there are police tactical units whose role is to directly engage terrorists and prevent terrorist attacks.Such units perform both in preventive actions, hostage rescue, and responding to ongoing attacks. Countries of all sizes can have highly trained counterterrorist teams. Tactics, techniques, and procedures for manhunting are under constant development.
These units are specially trained in military tactics and are equipped for close-quarters combat, with emphasis on stealth and performing the mission with minimal casualties. The units include assault teams, snipers, EOD experts, dog handlers, and intelligence officers. Most of these measures deal with terrorist attacks that affect an area or threaten to do so, or are lengthy situations such as shootouts and hostage takings that allow the counterterrorist units to assemble and respond; it is harder to deal with shorter incidents such as assassinations or reprisal attacks, due to the short warning time and the quick exfiltration of the assassins.[39]
The majority of counterterrorism operations at the tactical level are conducted by state, federal, and national law enforcement or intelligence agencies. In some countries, the military may be called in as a last resort. For countries whose military is legally permitted to conduct domestic law enforcement operations, this is not an issue, and such counterterrorism operations are conducted by their military.
Some counterterrorist actions of the 20th and 21st centuries are listed below. See list of hostage crises for a more extended list, including hostage-takings that did not end violently.
| Incident | Main locale | Hostage nationality | Kidnappers /hijackers | Counterterrorist force | width=300 | Results | |
|---|---|---|---|---|---|---|---|
| 1972 | Sabena Flight 571 | Tel Aviv-Lod International Airport, Israel | Mixed | Black September | Sayeret Matkal | 2 hijackers killed, 1 passenger died from wounds during raid. 2 passengers and 1 commando injured. 2 kidnappers captured. All other 96 passengers rescued. | |
| 1972 | Munich massacre | Munich, West Germany | Israeli | Black September | German Federal Border Guard | All hostages murdered; 5 kidnappers and 1 West German police officer killed. 3 kidnappers captured and released. This fatal result was the reason for the foundation of the German special counterterrorism unit GSG9 | |
| 1975 | AIA building hostage crisis | AIA building, Kuala Lumpur, Malaysia | Mixed. American and Swedish | Japanese Red Army | Special Actions Unit | All hostages released, all kidnappers flown to Libya. | |
| 1976 | Operation Entebbe | Entebbe airport, Uganda | Israelis and Jews. Non-Jewish hostages were released shortly after capture. | PFLP | Sayeret Matkal, Sayeret Tzanhanim, Sayeret Golani | All 7 hijackers, 45 Ugandan troops, 3 hostages, and 1 Israeli soldier were killed. 100 hostages rescued | |
| 1977 | Lufthansa Flight 181 | Initially over the Mediterranean Sea, south of the French coast; subsequently Mogadishu International Airport, Somalia | Mixed | PFLP | GSG 9, Special Air Service consultants | 1 hostage killed before the raid; 3 hijackers killed and 1 captured. 90 hostages rescued. | |
| 1980 | Casa Circondariale di Trani Prison riot | Trani, Italy | Italian | Red Brigades | Gruppo di intervento speciale (GIS) | 18 police officers rescued, all terrorists captured. | |
| 1980 | Iranian Embassy siege | London, UK | Mostly Iranian but some British | Democratic Revolutionary Movement for the Liberation of Arabistan | Special Air Service | 5 kidnappers killed, 1 kidnapper captured. 1 hostage killed prior to raid, 1 hostage killed by kidnapper during raid; 24 hostages rescued. 1 SAS operative received minor burns. | |
| 1979-1981 | Iran hostage crisis | Tehran, Iran | Americans | Muslim Student Followers of the Imam's Line | United States Army Special Forces, Delta Force, 75th Infantry Regiment (Ranger), CIA Special Activities Division, 1st Special Operations Wing | 8 US servicemen killed & 4 injured 1 Iranian civilian (alleged by Iranian Army) killed in Operation Eagle Claw. Negotiation finished in 1981. 53 hostages released. | |
| 1981 | Garuda Indonesia Flight 206 | Don Mueang Airport, Bangkok, Thailand | Mostly Indonesian, some Europeans/Americans | Komando Jihad | Kopassus assault group, RTAF securing perimeter | 5 hijackers killed (2 likely killed extrajudicially after raid),1 Kopassus operative killed, 1 pilot fatally wounded by terrorist, all hostages rescued. | |
| 1982 | Padua, Italy | American | Red Brigades | U.S. Army Intelligence Support Activity (ISA), Delta Force and Nucleo Operativo Centrale di Sicurezza (NOCS) | Hostage saved, capture of the entire terrorist cell. | ||
| 1983 | Turkish embassy attack | Lisbon, Portugal | Turkish | Armenian Revolutionary Army | GOE | 5 hijackers, 1 hostage, and 1 police officer killed, 1 hostage and 1 police officer wounded. | |
| 1985 | Achille Lauro hijacking | MS Achille Lauro off the Egyptian coast | Mixed | Palestine Liberation Organization | U.S. military, Navy SEALs turned over to Italian special forces (Gruppo di intervento speciale) | 1 hostage killed during hijacking, 4 hijackers convicted in Italy | |
| 1986 | Pudu Prison siege | Pudu Prison, Kuala Lumpur, Malaysia | Two doctors | Prisoners | Special Actions Unit | 6 kidnappers captured, 2 hostages rescued | |
| 1988 | Mothers Bus | Hijacked between Beer Sheva and Dimona, Israel | 11 passengers | Palestinian Liberation Organization | YAMAM | 3 hijacker killed, 3 hostages killed, 8 hostages rescued | |
| 1993 | Indian Airlines Flight 427 | Hijacked between Delhi and Srinagar, India | 141 passengers | Islamic terrorist (Mohammed Yousuf Shah) | National Security Guard | 1 hijacker killed, all hostages rescued. | |
| 1994 | Air France Flight 8969 | Marseille, France | Mixed | Armed Islamic Group of Algeria | GIGN | 4 hijackers killed. 3 hostages killed before the raid, 229 hostages rescued | |
| 1996 | Japanese embassy hostage crisis | Lima, Peru | Japanese and guests (800+) | Túpac Amaru Revolutionary Movement | Peruvian military and police mixed forces | All 14 kidnappers, 1 hostage, and 2 rescuers killed. | |
| 1996 | Mapenduma hostage crisis | Mapenduma, Indonesia | Mixed (19 Indonesians, 4 British, 2 Dutch, & 1 German) | Kelly Kwalik's Free Papua Movement (OPM) Group | Kopassus's SAT-81 Gultor CT Group, Kostrad's Infantry Battalion, Penerbad (Army Aviation) Mixed Forces | 8 kidnappers killed, 2 kidnappers captured. 2 hostages killed by kidnappers, 24 Hostages rescued. 5 Army Operatives killed in helicopter accident. | |
| 2000 | Sauk Siege | Perak, Malaysia | Malaysian (2 police officers, 1 soldier and 1 civilian) | Al-Ma'unah | Grup Gerak Khas and 20 Pasukan Gerakan Khas, mixed forces | 2 hostages, 2 rescuers, and 1 kidnapper killed. Other 28 kidnappers captured. | |
| 2001–2005 | Pankisi Gorge crisis | Pankisi Gorge, Kakheti, Georgia | Mixed, Al-Qaeda and Chechen rebels led by Ibn al-Khattab | 2,400 troops, 1,000 police officers | Terrorism threats in the gorge were repressed. | ||
| 2002 | Moscow theater hostage crisis | Moscow, Russia | Mixed, mostly Russian (900+) | Special Purpose Islamic Regiment | Spetsnaz | All 39 kidnappers and 129–204 hostages killed. 600–700 hostages freed. | |
| 2004 | Beslan school siege | Beslan, North Ossetia-Alania, Russia | Russian | Riyad-us Saliheen | MVD (including OMON), Russian army (including Spetsnaz), Russian police (Militsiya) | 334 hostages killed and hundreds wounded. 10–21 rescuers killed. 31 kidnappers killed, 1 captured. | |
| 2007 | Siege of Lal Masjid | Islamabad, Pakistan | Students and Tehrik-i-Taliban Pakistan | Pakistan Army and Rangers, Special Service Group | 91 students/militants killed, 50 militants captured. 10 SSG and 1 Ranger killed; 33 SSG, 3 Rangers, 8 soldiers wounded. 204 civilians injured. | ||
| 2007 | Kirkuk Hostage Rescue | Kirkuk, Iraq | Turkman child | Islamic State of Iraq Al Qaeda | PUK's Kurdistan Regional Government's Counter Terrorism Group | 5 kidnappers arrested, 1 hostage rescued | |
| 2008 | Operation Jaque | Colombia | Mixed | Revolutionary Armed Forces of Colombia | Columbian military | 15 hostages rescued. 2 kidnappers captured | |
| 2008 | Operations Dawn | Gulf of Aden, Somalia | Mixed | Somali pirates and militants | PASKAL and mixed international forces | Negotiation finished. 80 hostages released. RMN, including PASKAL navy commandos with mixed international forces patrolling the Gulf of Aden during this festive period.[40] [41] [42] | |
| 2008 | 2008 Mumbai attacks | Multiple locations in Mumbai city | Indian Nationals, Foreign tourists | Ajmal Qasab and other Pakistani nationals affiliated to Laskar-e-taiba | National Security Guard, MARCOS, Mumbai Police, Rapid Action Force | 141 Indian civilians, 30 foreigners, 15 police officers, and two NSG commandos were killed. 9 attackers killed, 1 attacker captured. 293 individuals injured | |
| 2009 | Maersk Alabama hijacking | Gulf of Aden, Somalia. | 23 crew | Somali pirates | U.S. Navy, SEAL Team Six | 3 kidnappers killed and 1 captured. All hostages rescued. | |
| 2009 | 2009 Lahore Attacks | Multiple locations in Lahore city | Pakistan | Lashkar-e-Taiba | Police Commandos, Army Rangers Battalion | March 3, The Sri Lankan cricket team attack – 6 members of the Sri Lankan cricket team were injured, 6 Pakistani police officers and 2 civilians killed.March 30, the Manawan Police Academy in Lahore attack – 8 gunmen, 8 police personnel and 2 civilians killed, 95 people injured, 4 gunmen captured. Plaza Cinema Chowk attack – 16 police officers, an army officer and unknown number of civilians killed. As many as 251 people injured. | |
| 2011 | Operation Dawn of Gulf of Aden | Gulf of Aden, Somalia | Koreans, Myanmar, Indonesian | Somali pirates and militants | Republic of Korea Navy Special Warfare Flotilla (UDT/SEAL) | 4+ kidnappers killed or missing (Jan 18). 8 kidnappers killed, 5 captured. All hostages rescued. | |
| 2012 | Lopota Gorge hostage crisis | Lopota Gorge, Georgia | Georgians | Ethnic Chechen, Russian, and Georgian militants | Special Operations Center, SOD, KUD, army special forces | 2 KUD members and one special forces corpsman killed, 5 police officers wounded. 11 kidnappers killed, 5 wounded, and 1 captured. All hostages rescued. | |
| 2013 | 2013 Lahad Datu standoff | Lahad Datu, Sabah, Malaysia | Malaysians | Royal Security Forces of the Sultanate of Sulu and North Borneo (Jamalul Kiram III's faction) | Malaysian Armed Forces, Royal Malaysia Police, Malaysian Maritime Enforcement Agency and joint counterterrorist forces, Philippine Armed Forces | 8 police officers (including 2 PGK commandos) and one soldier killed, 12 others wounded. 56 militants killed, 3 wounded, and 149 captured. All hostages rescued. 6 civilians killed and one wounded. | |
| 2017 | 2017 Isani flat siege | Isani district, Tbilisi, Georgia | Georgians | Chechen militants | State Security Service of Georgia, police special forces | 3 militants killed, including Akhmed Chatayev. One special forces officer killed during skirmishes. | |
| 2024 | Operation Golden Hand | Rafah, Gaza Strip | Israeli | Hamas | YAMAM and Shin Bet with support from the Israel Defense Forces | 67–100+ Palestinians killed, all hostages rescued. | |
The scope for counterterrorism systems is very large in physical terms and in other dimensions, such as type and degree of terrorist threats, political and diplomatic ramifications, and legal concerns. Ideal counterterrorist systems use technology to enable persistent intelligence, surveillance and reconnaissance missions, and potential actions. Designing such a system-of-systems comprises a major technological project.[43]
A particular design problem for counterterrorist systems is the uncertainty of the future: the threat of terrorism may increase, decrease or remain the same, the type of terrorism and location are difficult to predict, and there are technological uncertainties. A potential solution is to incorporate engineering flexibility into system design, allowing for flexibility when new information arrives. Flexibility can be incorporated in the design of a counter-terrorism system in the form of options that can be exercised in the future when new information is available.
While some countries with longstanding terrorism problems have law enforcement agencies primarily designed to prevent and respond to terror attacks,[44] in other nations, counterterrorism is a relatively more recent objective of law enforcement agencies.[45] [46]
Though some civil libertarians and criminal justice scholars have criticized efforts of law enforcement agencies to combat terrorism as futile and expensive[47] or as threats to civil liberties, other scholars have analyzed the most important dimensions of the policing of terrorism as an important dimension of counter-terrorism, especially in the post-9/11 era, and have discussed how police view terrorism as a matter of crime control. Such analyses highlight the civilian police role in counterterrorism next to the military model of a war on terror.[48]
Pursuant to passage of the Homeland Security Act of 2002, federal, state, and local law enforcement agencies began to systemically reorganize.[49] [50] Two primary federal agencies, the Department of Justice (DOJ) and the Department of Homeland Security (DHS), house most of the federal agencies that are prepared to combat domestic and international terrorist attacks. These include the Border Patrol, the Secret Service, the Coast Guard and the FBI.
Following suit from federal changes pursuant to 9/11, however, most state and local law enforcement agencies began to include a commitment to "fighting terrorism" in their mission statements.[51] [52] Local agencies began to establish more patterned lines of communication with federal agencies. Some scholars have doubted the ability of local police to help in the war on terror and suggest their limited manpower is still best utilized by engaging community and targeting street crimes.[47]
While counter-terror measures (most notably heightened airport security, immigrant profiling[53] and border patrol) have been adapted during the last decade, to enhance counter-terror in law enforcement, there have been remarkable limitations to assessing the actual utility/effectiveness of law enforcement practices that are ostensibly preventative.[54] Thus, while sweeping changes in counterterrorist rhetoric redefined most American post 9/11 law enforcement agencies in theory, it is hard to assess how well such hyperbole has translated into practice.
In intelligence-led policing (ILP) efforts, the most quantitatively amenable starting point for measuring the effectiveness of any policing strategy (i.e.: Neighborhood Watch, Gun Abatement, Foot Patrols, etc.) is usually to assess total financial costs against clearance rates or arrest rates. Since terrorism is such a rare event phenomena,[55] measuring arrests or clearance rates would be a non-generalizable and ineffective way to test enforcement policy effectiveness. Another methodological problem in assessing counterterrorism efforts in law enforcement hinges on finding operational measures for key concepts in the study of homeland security. Both terrorism and homeland security are relatively new concepts for criminologists, and academicians have yet to agree on the matter of how to properly define these ideas in a way that is accessible.
See main article: List of counter-terrorism agencies.
Given the nature of operational counterterrorism tasks national military organizations do not generally have dedicated units whose sole responsibility is the prosecution of these tasks. Instead the counterterrorism function is an element of the role, allowing flexibility in their employment, with operations being undertaken in the domestic or international context.
In some cases the legal framework within which they operate prohibits military units conducting operations in the domestic arena; United States Department of Defense policy, based on the Posse Comitatus Act, forbids domestic counterterrorism operations by the U.S. military. Units allocated some operational counterterrorism tasks are frequently special forces or similar assets.
In cases where military organisations do operate in the domestic context some form of formal handover from the law enforcement community is regularly required, to ensure adherence to the legislative framework and limitations. such as the Iranian Embassy siege, the British police formally turned responsibility over to the Special Air Service when the situation went beyond police capabilities.