The Encyclopedia is a project of the Geneva Academy of International Humanitarian Law and Human Rights launched on 2 December 2013. The Enyclopedia aims to provide accurate, up-to-date information on weapons, the effects of their use, and their regulation under public international law, in a format that is accessible to non-specialists.+ Find out more
Barrel bombs are not specifically prohibited under international law.For a brief legal analysis, see T. Rodenhäuser, 'The Use of ‘Do it Yourself’ Barrel Bombs under International Law', EJIL: Talk!, 10 April 2014. Like other improvised weapons, these 'flying IEDs' are not made to exact specifications and differ in shape, size, composition, and fuzing mechanism, and, thus, also in their effects.For a technical discussion, see R. M. Lloyd, ‘Syria's Barrel Bomb Technology Relative To Aleppo Syria Attacks - The Good, The Bad And The Ugly’, Brown Moses Blog, 22 December 2013. Certain barrel bombs may, however, meet the definition of a prohibited weapon under international law. In addition, barrel bombs used as a means of warfare, especially in or near a concentration of civilians, may violate general rules on the conduct of hostilities.
Barrel bombs with an incendiary filling may in some cases meet the definition of an incendiary weapon under international law. Use of such barrel bombs for attacks on targets within a concentration of civilians would violate 1980 Protocol III to the Convention on Certain Conventional Weapons. According to the International Committee of the Red Cross (ICRC), the specific prohibition of the Protocol on the use of air-delivered incendiary weapons had, however, not attained customary status in 2005.ICRC Customary IHL Study, Rule 84. The Commission on Inquiry on Syria further considered that barrel bombs ‘built as de facto incendiary weapons’ violate ‘rules of international humanitarian law prohibiting the use of weapons that cause superfluous injury, unnecessary suffering or that are indiscriminate by nature’.7th Report of the IICI on Syria, UN doc. A/HRC/25/65, 12 February 2014, §42. See the entry on the Commission on this point.
Barrel bombs containing toxic chemicals (such as chlorine) can meet the definition of a chemical weapon, prohibited under the 1993 Chemical Weapons Convention and under customary international law. There have been allegations of Syrian forces using barrel bombs containing chemical agents. In its eighth report (13 August 2014), the Commission of Inquiry on Syria found that reasonable grounds existed to believe that chemical agents, likely chlorine, were used on Kafr Zeita, Al-Tamana’a and Tal Minnis in eight incident and that reasonable grounds existed to believe that those agents were dropped in barrel bombs from government helicopters. The Commission recalled that chlorine gas is a chemical weapon as defined in the 1993 Chemical Weapons Convention, whose use is prohibited in all circumstances under customary IHL and is a war crime under the Rome Statute of the International Criminal Court.8th Report of the Commission of Inquiry on Syria, UN doc. A/HRC/27/60, 13 August 2014, §§177-8; 'Evidence From 2 Weeks Of Chlorine Barrel Bomb Attacks', Brown Moses Blog, 22 April 2014.
More generally, the use of barrel bombs as a means of warfare (i.e. for the conduct of hostilities during an armed conflict) raises concerns under the rule on distinction in attacks. Due to the potentially wide area affected by blast, fragmentation, heat/fire and other effects of barrel bombs and their inaccuracy of delivery (especially when they are dropped from a transport plane or a helicopter without a guidance mechanism), the use of barrel bombs in a populated area bears a high risk of violating the prohibition on indiscriminate attacks and the prohibition on disproportionate attacks.See, e.g., 8th Report of the Commission of Inquiry on Syria, UN doc. A/HRC/27/60, 13 August 2014, §102.
Several UN Security Council resolutions on Syria mention barrel bombs in connection with concerns about indiscriminate effects. In Resolution 2139 (2014), the Security Council demands that ‘all parties immediately cease … the indiscriminate employment of weapons in populated areas, including shelling and aerial bombardment, such as the use of barrel bombs...’, and Resolution 2165 (2014) expresses ‘grave alarm in particular at the continuing indiscriminate attacks in populated areas, including an intensified campaign of aerial bombings and the use of barrel bombs in Aleppo and other areas’.See also UN Security Council Resolution 2191 (2014) and the report of the UN Secretary-General on children and armed conflict, UN doc. S/2014/339 of 15 May 2014.
The Commission of Inquiry on Syria found that the use of barrel bombs in the context of densely populated areas in Syria amounted to ‘area bombardment’, a form of indiscriminate attack specifically prohibited under IHL.ICRC Customary IHL Study, Rule 13. This prohibition is also reflected in 1977 Additional Protocol I, Art. 51(5)(a). See the entry on the Commission on this point.
In light of their inaccuracy of delivery and area effects, barrel bombs have been deemed to be indiscriminate weapons, especially in the context of a populated area. The Commission of Inquiry on Syria has repeatedly called on the Syrian government to ‘halt immediately the use of illegal and indiscriminate weapons, including barrel bombs’.9th Report of Commission of Inquiry on Syria, UN doc. A/HRC/28/69, 5 February 2015, §§78, 144. See the entry on the Commission on this point. The non-governmental organisation, Human Rights Watch, has described barrel bombs dropped from helicopters into urban areas in Iraq as indiscriminate weapons: ‘The extreme unlikelihood that barrel bombs can be used to accurately target legitimate military objectives in populated areas almost always makes their use indiscriminate and in violation of the laws of war. … Human Rights Watch found that many of the munitions used in these strikes are “dumb bombs,” including barrel bombs and unguided air-dropped bombs that lack guidance systems and so are, like their method of delivery, inherently indiscriminate if used in populated areas.’Human Rights Watch, 'Iraq: Civilian Toll of Government Airstrikes', 23 July 2014.
Barrel bomb use in populated areas of Syria has also been described as a ‘tactic that spreads terror among the civilian population’. Acts or threats of violence the primary purpose of which is to spread terror among the civilian population are prohibited under customary IHL.8th Report of the Commission of Inquiry on Syria, UN doc. A/HRC/27/60, 13 August 2014, §102; 7th Report of the Commission of Inquiry on Syria, UN doc. A/HRC/25/65, 12 February 2014, §86 and Annex VI, §4; ICRC Customary IHL Study, 2005, Rule 2. 'Indiscriminate and widespread shelling', and 'the regular bombardment of cities' are cited in practice as amounting to a violation of that rule. In this regard, parallels may be drawn with the case of Dragomir Milošević before the ICTY. Although not directly concerned with barrel-bombs, that case dealt with the use of ‘modified air-bombs’, an improvised, powerful weapon, launched from the ground, into a populated area (Sarajevo). The Tribunal described that weapon as a ‘highly inaccurate and indiscriminate weapon’. The repeated use of that weapon in Sarajevo and the pattern of grave harm caused to the civilian population served as indicators of intent to terrorize the civilian population and were aggravating factors in the sentencing.
Last updated on: 16 August 2016