CONTACT

While we often hear about the risk nuclear weapons or new technologies pose to the protection of  civilians in war time, most of the IHL violations today are caused by the use of conventional weapons. Some of those weapons, in particular anti-personnel landmines and cluster munitions continue to inflict severe suffering on civilians long after conflicts end. Since 1999, over 165,000 people have reportedly been killed or injured by mines (Landmine Monitor 2025). In 2024 alone, 6,279 lives were reportedly shattered, with 86 per cent of casualties being civilians and 46 per cent children - the highest annual toll since 2020 (Landmine Monitor 2025). Cluster munitions, on their side, have reportedly caused over 24,000 recorded casualties worldwide, with many more unreported (Cluster Munition Monitor 2025). The impact extends far beyond immediate casualties. If we consider the use of explosive weapons in populated areas, such use results in civilians, who make up about 90 per cent of the victims, facing lifelong disabilities, shattered healthcare systems, and destroyed infrastructure like schools, water, and electricity. Families are displaced, communities fractured, and generations burdened with trauma no one should endure.

This highlight provides a brief overview of the regulation of conventional weapons under international humanitarian law (IHL), and brings together relevant teaching materials, including case studies illustrating the application of these rules in different armed conflicts.

What are Conventional Weapons?

Conventional weapons are means of warfare that cannot be considered as weapons of mass destruction. They cover a broad range of weapons employed in armed conflicts, including small arms, battle tanks, missiles, laser weapons, incendiary weapons, mines, cluster munitions, expanding (dum-dum) bullets, and non-detectable fragments, among others. The lawfulness of conventional weapons and of their usage, is assessed by the rules of IHL governing means and methods of warfare.

General Limits and Specific Prohibitions of Conventional Weapons 

The use of weapons in armed conflict is never unlimited. IHL prohibits all weapons, including conventional ones, from causing indiscriminate effects, unnecessary suffering, superfluous injury, or widespread, long-term and severe damage to the environment (Additional Protocol I (AP I), Arts. 35 and 51(4); ICRC Customary IHL Rules 70, 71, 45, 11, 12). In addition, IHL submits the use of conventional weapons to the rules on the conduct of hostilities, requiring parties to make sure that such weapons comply with the rules of distinction, proportionality and precautions, among other rules. These rules, rooted in foundational instruments such as the St. Petersburg Declaration (1868) and the Hague Declarations of 1899 and 1907, as well as the Hague Convention of 1907 and detailed out in AP I, Arts. 48-58, are further reinforced by the obligation of states to review the lawfulness of new weapons prior to their deployment (AP I, Art. 36), and the obligation to respect and ensure respect for IHL in all circumstances (Common Article 1 of the Geneva Conventions). Moreover, in situations where neither treaty nor customary law provides specific guidance, the use of weapons remains governed by  principle  of humanity and the dictates of public conscience.

Over time, specific prohibitions and/or restrictions have been adopted to prevent indiscriminate or unnecessary effects of certain weapons. The Convention on Certain Conventional Weapons (CCW) and its Protocols establish a legal framework for regulating, restricting, and in certain cases prohibiting the use of specific weapons, including landmines, booby traps, incendiary weapons, weapons primarily injuring by non-detectable fragments, blinding laser weapons, and explosive remnants of war, in both international and non-international armed conflicts. In 2006, the Third Review Conference of the CCW adopted a decision establishing a compliance mechanism for the Convention, which requires states parties to adopt national implementing legislation, disseminate the Convention and its Protocols among both civilian populations and armed forces, and submit annual reports on compliance, among other obligations. The CCW is further designed as an adaptable instrument, enabling states parties to respond to emerging humanitarian concerns through the negotiation and adoption of additional protocols addressing other categories of conventional weapons, as provided under Article 8(2) of the Convention.

Other specific instruments include the 1997 Anti-Personnel Mine Ban Convention (Ottawa Treaty) and the 2008 Convention on Cluster Munitions, which go beyond regulation by banning use of anti-personnel mines and cluster munitions, along with producing, transferring and stockpiling, while also requiring clearance of affected areas and assistance to victims. In addition, the 2022 Political Declaration on Strengthening the Protection of Civilians from the Humanitarian Consequences of Explosive Weapons in Populated Areas (EWIPA) reinforces international efforts to protect civilians by addressing the humanitarian impact of explosive weapons in populated areas.

Transfer of Conventional Weapons 

The widespread availability and misuse of conventional arms and ammunition contribute significantly to human suffering in armed conflicts, and, for some weapons, even years after wars have ended. All states, regardless of whether they are parties to an armed conflict, must respect and ensure respect for IHL in all circumstances. This obligation requires states to consider the risk that the transfer of arms and ammunition may facilitate violations of IHL. In addition to this general duty, states are also bound by regional instruments regulating the transfer of conventional weapons (see here, here and here). At the universal level, the primary treaty governing such transfers is the Arms Trade Treaty (ATT) of 2013. One of the central purposes of the ATT is to reduce human suffering, particularly the harm that can result from the uncontrolled transfer of conventional weapons. To achieve this purpose, the treaty  either prohibits the transfer of conventional arms, if the transferring state has knowledge, at the time of authorization, that such arms would be used to commit war crimes or other violations  of international law (Article 6) or subjects such transfers to detailed assessment criteria (Article 7). Similarly, states parties are required to regulate and report on the import and export of such weapons within their territories. 

Conclusion

Conventional weapons have long been and continue to be widely used in armed conflicts. The regulation and prohibition of such weapons are not new. They are part of a longstanding tradition that seeks to balance military necessity with humanitarian concerns, an effort that is even more relevant as means of warfare continue to evolve. While international treaties like the Ottawa Treaty and the Convention on Cluster Munitions have made strides, by resulting in destroying millions of mines and cluster munitions and reducing their use, their impact is overshadowed by ongoing humanitarian suffering. With over 160 states are parties to the Ottawa Treaty and 112 to the Convention on Cluster Munitions, progress is undeniable, yet fragile. The continued use of these weapons, the withdrawal of some states from some treaties, and identified gaps in regulation, such as for lethal autonomous weapons, expose civilians to unnecessary harm. To truly protect lives and prevent unnecessary suffering, stronger global commitment, broader ratification, and stricter adherence to treaties prohibiting or regulating conventional weapons are urgently needed.

Casebook resources

The Law

In the “Law”, conventional weapons are addressed under the section on the Conduct of Hostilities, which examines the means and methods of warfare, including the prohibited or restricted use of certain weapons. 

The Practice

The following are the relevant case studies from ‘the Practice’ section:

Conventional Weapons in General

Anti-personnel Landmines

Cluster Munitions

Incendiary Weapons

Non-Detectable Fragments

Blinding Laser Weapons

Explosive Remnants of War

Explosive Weapons in Populated Areas

Autonomous Weapons

Arms Trade

A – Z

The following definitions are relevant explore how IHL regulates the use of conventional weapons: 

Additional protocols; Ammunition; Armed conflict; Booby-traps; Children; Civilians; Civilian objects; Civilian population; Cluster munitions; Conduct of hostilities; Conventional weapons; Customary International Humanitarian Law; Declaration of St Petersburg; Displacement; Distinction; Dum-dum bullets; Environment; Explosive remnants of war;   Fragmentation munitions; Fundamental principles of IHL; Geneva Conventions; Humanity; Implementation; Incendiary weapons; Indiscriminate attacks;  Laser weapons; Martens Clause; Means of warfare; Methods of warfare; Militar necessity; Military objectives; Mines; Non-detectable fragments; Non-international armed conflict; Respect and Ensure Respect; Unnecessary suffering (or superfluous injury); Violations; Weapons.

To Go Further 

Conventional Weapons in General

  • ICRC, 1980 Convention on Certain Conventional Weapons (2021)
  • William Boothby, “Control in Weapons Law” in Rogier Bartels, Jeroen C. van den Boogaard, Paul A. L. Ducheine, Eric Pouw and Joop Voetelink (eds), Military Operations and the Notion of Control under International Law, TMC Asser Press, The Hague, 2021, p. 369 Accessed here

Landmines

Blinding Laser Weapons

Explosive Remnants of War

Incendiary Weapons 

Explosive Weapons in Populated Areas

Autonomous Weapons

New Weapons

Arms Trade