Inside Cluster Munitions

Cluster munitions are designed to amplify both the destructive power and the psychological impact of conventional weapons. Instead of carrying a single large warhead that causes heavy localized destruction at the point of impact, a cluster munition contains dozens or even hundreds of smaller bomblets intended to disperse over a wide area, increasing casualties, extending the damage zone, and complicating rescue and emergency operations. Cluster munitions can be delivered by artillery shells, missiles, or aerial bombs, and can be launched from land, sea, or air. According to media reports, some Iranian ballistic missiles in the Khorramshahr, Emad, and Qadr families also come in versions fitted with cluster warheads. Iran reportedly launched several such missiles at Israel during Operation Rising Lion in June 2025 and Operation Roaring Lion in 2026.

When delivered by a ballistic missile, cluster submunitions are released at an altitude of several kilometers by a spring-loaded mechanism designed to disperse them over a wide area. The same mechanism also arms the bomblets by removing the safety device that prevents premature detonation. High-altitude release poses a challenge for interception systems, which are generally designed to target the missile itself and are ineffective against bomblets as small as hand grenades. In some cases, the submunitions are equipped with parachutes or other devices to slow their descent. This prolongs the time during which people must remain in protected areas and, if there is wind, can widen the impact area even further.

Cluster munitions come in many forms and are designed for different purposes. Submunitions intended to harm people – whether soldiers or civilians – often contain metal pellets in addition to the explosive charge. Many also have a metal casing that breaks apart on detonation, producing sharp fragments of its own. Some are fitted with a mechanism that detonates them just before impact, increasing the area over which the metal fragments are dispersed. Others are designed for use against armored vehicles and built to penetrate metal armor. Another type of cluster munition is incendiary cluster ordnance, whose submunitions contain flammable material such as phosphorus and are intended to ignite widespread fires in the target area. Some cluster bombs are designed to disable airfields. Built like miniature bunker-buster bombs, they penetrate the runway before exploding, maximizing the damage. There are even cluster munitions intended to disrupt power grids by scattering long conductive wires that create short circuits.

One of the main problems with cluster bombs is that not all of them detonate. This forces security forces to spend valuable time locating and neutralizing unexploded ordnance. A particularly dangerous variant uses delayed-action submunitions, designed to explode some time after landing in order to put rescue and emergency crews at greater risk. In some cases, they are fitted with a mechanism that is triggered only when someone steps on or touches the munition, effectively turning them into a form of air-delivered landmine.

Another type of cluster missile carries a warhead that breaks apart in flight, releasing multiple bombs that spread through the air much like standard cluster munitions. A more advanced version of the same concept is the MIRV—short for Multiple Independently targetable Reentry Vehicle—in which each warhead has its own propulsion system. In some versions, those warheads can even steer toward specific targets, for example by locking onto the heat signature of a vehicle’s engine. Several reports have suggested that Iran launched missiles with separating warheads, but at the time of writing it remains unclear whether Iran used such weapons against Israel, or whether the missiles in question were simply standard cluster missiles.

A War Crime

Cluster munitions also have several drawbacks from the attacker’s point of view. They are relatively expensive to produce and less precise, since it is usually impossible to control where each individual submunition will land. Some submunitions are equipped with guidance systems for specific targets, but that makes the weapon even more expensive. And when civilians follow safety instructions and take shelter as directed, the damage caused by each individual bomblet is often limited.

The use of cluster munitions is considered a war crime. So far, 111 countries have signed the convention banning their use, production, and transfer. Iran, Israel, and the United States are not parties to the convention. Israel has been accused several times of using such weapons, mainly in Lebanon. The signatories, meanwhile, include Lebanon, Iraq, and even “Palestine,” as it is defined in the convention documents.

There is a grim mismatch between the name and the weapon. Cluster munition sounds clinical, technical, almost bureaucratic—for a weapon designed to scatter explosives over a wide area. Worse, its danger often outlasts the attack itself: unexploded bomblets can remain on the ground long afterward, threatening civilians, complicating rescue efforts, and extending the human cost of war far beyond the moment of impact.

The term cluster munition has the technical, bureaucratic sound of military jargon. The reality is far more brutal: a weapon designed to spread explosives over a wide area, often leaving danger behind long after the initial strike. Unexploded bomblets can remain scattered on the ground for hours, days, or longer, threatening civilians, complicating rescue efforts, and extending the human cost of war far beyond the moment of impact.

Translated with the assistance of ChatGPT. Edited, revised, and reviewed by the editorial staff of the Davidson Institute of Science Education.