International legal instruments

Terrorism has been on the international agenda since 1934, when the League of Nations took the first major step towards outlawing the scourge by discussing a draft convention for the prevention and punishment of terrorism. Although the Convention was eventually adopted in 1937, it never came into force.

Since 1963, the international community has elaborated 14 universal legal instruments and four amendments to prevent terrorist acts. Those instruments were developed under the auspices of the United Nations and its specialized agencies and the International Atomic Energy Agency (IAEA) and are open to participation by all Member States. In 2005, the international community also introduced substantive changes to three of these universal instruments to specifically account for the threat of terrorism; on 8 July of that year States adopted the Amendments to the Convention on the Physical Protection of Nuclear Material, and on 14 October they agreed to both the Protocol of 2005 to the Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation and the Protocol of 2005 to the Protocol for the Suppression of Unlawful Acts against the Safety of Fixed Platforms Located on the Continental Shelf.

Two more legal instruments were added in 2010: the 2010 Convention on the Suppression of Unlawful Acts Relating to International Civil Aviation and the 2010 Protocol Supplementary to the Convention for the Suppression of Unlawful Seizure of Aircraft. These treaties further criminalize the act of using civil aircraft as a weapon, and of using dangerous materials to attack aircraft or other targets on the ground. The unlawful transport of biological, chemical and nuclear weapons and their related material becomes punishable under the treaties. Moreover, directors and organizers of attacks against aircraft and airports will have no safe haven. Making a threat against civil aviation may also trigger criminal liability.

Currently Member States are negotiating an additional international treaty, a draft comprehensive convention on international terrorism. This convention would complement the existing framework of international anti-terrorism instruments and would build on key guiding principles already present in recent anti-terrorist conventions:  the importance of criminalization of terrorist offences, making them punishable by law and calling for prosecution or extradition of the perpetrators; the need to eliminate legislation which establishes exceptions to such criminalization on political, philosophical, ideological, racial, ethnic, religious or similar grounds; a strong call for Member States to take action to prevent terrorist acts; and emphasis on the need for Member States to cooperate, exchange information and provide each other with the greatest measure of assistance in connection with the prevention, investigation and prosecution of terrorist acts.

In the United Nations Global Counter-Terrorism Strategy which was adopted by the General Assembly on 8 September 2006, Member States underscored the importance of existing international counter-terrorism instruments by pledging to consider becoming parties to them without delay and implementing their provisions.

International Conventions

Here is a summary of the 14 major legal instruments and additional amendments dealing with terrorism. (for the full text of the convention see: United Nations Treaty Collection, conventions on terrorism):

1. 1963 Convention on Offences and Certain Other Acts Committed On Board Aircraft
(Aircraft Convention)

  • Applies to acts affecting in-flight safety;
  • Authorizes the aircraft commander to impose reasonable measures, including restraint, on any person he or she has reason to believe has committed or is about to commit such an act, where necessary to protect the safety of the aircraft; and
  • Requires contracting States to take custody of offenders and to return control of the aircraft to the lawful commander.

2. 1970 Convention for the Suppression of Unlawful Seizure of Aircraft 
(Unlawful Seizure Convention)

  • Makes it an offence for any person on board an aircraft in flight to "unlawfully, by force or threat thereof, or any other form of intimidation, [to] seize or exercise control of that aircraft" or to attempt to do so;
  • Requires parties to the convention to make hijackings punishable by "severe penalties"
  • Requires parties that have custody of offenders to either extradite the offender or submit the case for prosecution; and
  • Requires parties to assist each other in connection with criminal proceedings brought under the Convention.

2010 Protocol Supplementary to the Convention for the Suppression of Unlawful Seizure of Aircraft 

3. 1971 Convention for the Suppression of Unlawful Acts against the Safety of Civil Aviation
(Civil Aviation Convention)

  • Makes it an offence for any person unlawfully and intentionally to perform an act of violence against a person on board an aircraft in flight, if that act is likely to endanger the safety of the aircraft; to place an explosive device on an aircraft; to attempt such acts; or to be an accomplice of a person who performs or attempts to perform such acts;
  • Requires parties to the Convention to make offences punishable by "severe penalties"; and
  • Requires parties that have custody of offenders to either extradite the offender or submit the case for prosecution.

4. 1973 Convention on the Prevention and Punishment of Crimes Against Internationally Protected Persons
(Diplomatic Agents Convention)

  • Defines an "internationally protected person" as a Head of State, Minister for Foreign Affairs, representative or official of a State or international organization who is entitled to special protection in a foreign State, and his/her family; and
  • Requires parties to criminalize and make punishable "by appropriate penalties which take into account their grave nature" the intentional murder, kidnapping or other attack upon the person or liberty of an internationally protected person, a violent attack upon the official premises, the private accommodations, or the means of transport of such person; a threat or attempt to commit such an attack; and an act "constituting participation as an accomplice".

5. 1979 International Convention against the Taking of Hostages
(Hostages Convention)

  • Provides that "any person who seizes or detains and threatens to kill, to injure, or to continue to detain another person in order to compel a third party, namely, a State, an international intergovernmental organization, a natural or juridical person, or a group of persons, to do or abstain from doing any act as an explicit or implicit condition for the release of the hostage commits the offence of taking of hostage within the meaning of this Convention". 

6. 1980 Convention on the Physical Protection of Nuclear Material
(Nuclear Materials Convention)

  • Criminalizes the unlawful possession, use, transfer or theft of nuclear material and threats to use nuclear material to cause death, serious injury or substantial property damage.

Amendments to the Convention on the Physical Protection of Nuclear Material

  • Makes it legally binding for States Parties to protect nuclear facilities and material in peaceful domestic use, storage as well as transport; and
  • Provides for expanded cooperation between and among States regarding rapid measures to locate and recover stolen or smuggled nuclear material, mitigate any radiological consequences or sabotage, and prevent and combat related offences.

7. 1988 Protocol for the Suppression of Unlawful Acts of Violence at Airports Serving International Civil Aviation, supplementary to the Convention for the Suppression of Unlawful Acts against the Safety of Civil Aviation (Extends and supplements the Montreal Convention on Air Safety)
(Airport Protocol)

  • Extends the provisions of the Montreal Convention (see No. 3 above) to encompass terrorist acts at airports serving international civil aviation.

8. 1988 Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation
(Maritime Convention)

  • Establishes a legal regime applicable to acts against international maritime navigation that is similar to the regimes established for international aviation; and
  • Makes it an offence for a person unlawfully and intentionally to seize or exercise control over a ship by force, threat, or intimidation; to perform an act of violence against a person on board a ship if that act is likely to endanger the safe navigation of the ship; to place a destructive device or substance aboard a ship; and other acts against the safety of ships.

2005 Protocol to the Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation

  • Criminalizes the use of a ship as a device to further an act of terrorism;
  • Criminalizes the transport on board a ship various materials knowing that they are intended to be used to cause, or in a threat to cause, death or serious injury or damage to further an act of terrorism;
  • Criminalizes the transporting on board a ship of persons who have committed an act of terrorism; and
  • Introduces procedures for governing the boarding of a ship believed to have committed an offence under the Convention.

9. 1988 Protocol for the Suppression of Unlawful Acts Against the Safety of Fixed Platforms Located on the Continental Shelf
(Fixed Platform Protocol)

  • Establishes a legal regime applicable to acts against fixed platforms on the continental shelf that is similar to the regimes established against international aviation.

2005 Protocol to the Protocol for the Suppression of Unlawful Acts against the Safety of Fixed Platforms Located on the Continental Shelf

  • Adapts the changes to the Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation to the context of fixed platforms located on the continental shelf.

10. 1991 Convention on the Marking of Plastic Explosives for the Purpose of Detection
(Plastic Explosives Convention)

  • Designed to control and limit the used of unmarked and undetectable plastic explosives (negotiated in the aftermath of the 1988 Pan Am flight 103 bombing);
  • parties are obligated in their respective territories to ensure effective control over "unmarked" plastic explosive, i.e., those that do not contain one of the detection agents described in the Technical Annex to the treaty;
  • Generally speaking, each party must, inter alia, take necessary and effective measures to prohibit and prevent the manufacture of unmarked plastic explosives; prevent the movement of unmarked plastic explosives into or out of its territory; exercise strict and effective control over possession and transfer of unmarked explosives made or imported prior to the entry into force of the Convention; ensure that all stocks of unmarked explosives not held by the military or police are destroyed, consumed, marked, or rendered permanently ineffective within three years; take necessary measures to ensure that unmarked plastic explosives held by the military or police are destroyed, consumed, marked or rendered permanently ineffective within fifteen years; and, ensure the destruction, as soon as possible, of any unmarked explosives manufactured after the date of entry into force of the Convention for that State.

11. 1997 International Convention for the Suppression of Terrorist Bombings
(Terrorist Bombing Convention)

  • Creates a regime of universal jurisdiction over the unlawful and intentional use of explosives and other lethal devices in, into, or against various defined public places with intent to kill or cause serious bodily injury, or with intent to cause extensive destruction of the public place.

12. 1999 International Convention for the Suppression of the Financing of Terrorism
(Terrorist Financing Convention)

  • Requires parties to take steps to prevent and counteract the financing of terrorists, whether direct or indirect, through groups claiming to have charitable, social or cultural goals or which also engage in illicit activities such as drug trafficking or gun running;
  • Commits States to hold those who finance terrorism criminally, civilly or administratively liable for such acts; and
  • Provides for the identification, freezing and seizure of funds allocated for terrorist activities, as well as for the sharing of the forfeited funds with other States on a case-by-case basis. Bank secrecy is no longer adequate justification for refusing to cooperate.

13. 2005 International Convention for the Suppression of Acts of Nuclear Terrorism
(Nuclear Terrorism Convention)

  • Covers a broad range of acts and possible targets, including nuclear power plants and nuclear reactors;
  • Covers threats and attempts to commit such crimes or to participate in them, as an accomplice;
  • Stipulates that offenders shall be either extradited or prosecuted;
  • Encourages States to cooperate in preventing terrorist attacks by sharing information and assisting each other in connection with criminal investigations and extradition proceedings; and
  • Deals with both crisis situations (assisting States to solve the situation) and post-crisis situations (rendering nuclear material safe through the International Atomic Energy Agency (IAEA).

14. 2010 Convention on the Suppression of Unlawful Acts Relating to International Civil Aviation
(New civil aviation convention)

  • Criminalizes the act of using civil aircraft as a weapon to cause death, injury or damage;
  • Criminalizes the act of using civil aircraft to discharge biological, chemical and nuclear (BCN) weapons or similar substances to cause death, injury or damage, or the act of using such substances to attack civil aircraft;
  • Criminalizes the act of unlawful transport of BCN weapons or certain related material;
  • A cyber attack on air navigation facilities constitutes an offence;
  • A threat to commit an offence may be an offence by itself, if the threat is credible.
  • Conspiracy to commit an offence, or its equivalence, is punishable.