The recent escalation in missile exchanges between Israel and Iran has refocused attention on the legal status of cluster munitions, a weapon category often defined more by its controversy than its technical utility. While Jerusalem has characterized recent Iranian strikes as war crimes, the legal reality is governed not by a blanket ban but by the application of customary international law.
Neither Israel nor the Islamic Republic of Iran is party to the 2008 Convention on Cluster Munitions, meaning that they are not bound by an absolute, treaty-based prohibition.
“Customary international law does not prohibit the use of cluster munitions per se,” Col. (res.) Dr. Liron Libman, former head of the IDF’s International Law Division, explained in an interview with The Jerusalem Post on Monday.
“Only states that are parties to the CCM have undertaken an obligation not to use, develop, or transfer cluster munitions.”
Libman noted that major military powers such as the United States, Russia, China, India, and Turkey have avoided the treaty because the weapons are “considered effective against certain types of military targets, for example, military airfields or other targets spread over a large area.” However, he warned, those same characteristics that make them effective also make them “legally problematic when used in the vicinity of civilians.”
The case against the Iranian regime rests on whether its recent salvos, reportedly involving Khorramshahr-4 missiles, violate the principles of distinction and proportionality.
“International law prohibits the intentional targeting of civilians and also prohibits indiscriminate attacks,” Libman said. “Intentionally targeting civilians constitutes a war crime.”
Based on media reports of Iranian munitions impacting residential areas, Libman suggested that the regime may be “deliberately targeting the Israeli civilian population” or conducting “indiscriminate attacks” using weapons that lack the precision required to hit even a wide-area military objective.
Israel’s own use of these munitions remains a point of friction, particularly regarding the reliability of its technology. While military industry figures often cite “smart” submunitions with failure rates as low as 0.01%, historical audits suggest a much wider gap between laboratory tests and battlefield reality.
The Winograd Report
The Winograd Commission’s audit of the Second Lebanon War (2006) remains a critical benchmark for this skepticism. The commission identified three central problems: an inherent lack of accuracy in most delivery methods, a wide dispersal area of “bomblets,” and the high number of “duds” that remain active long after a strike.
The commission found that actual field failure rates for artillery-based cluster munitions ranged from 12% to 18%, while rocket-launched systems averaged about 5%.
Libman noted that claims regarding failure rates – including those made by UN bodies – should be assessed carefully, as discrepancies often stem from “methodological issues, such as the conditions of use, the specific munition type, and how unexploded ordnance is counted.”
The Winograd final report highlighted that, in 2006, duds were found inside Lebanese villages despite standing orders from Israel’s chief of staff prohibiting fire into inhabited areas.
The commission identified a “lack of clarity in orders” and “disciplinary failures” as key reasons for these outcomes, concluding that using such weapons in areas where residents are expected to return is an “unacceptable expansion” of rules of engagement, which require the most stringent oversight.
However, the report stressed that it found no deliberate violation of international law by the IDF and that orders given – before and during the war – emphasized the need to avoid civilian harm.
The 2006 framework established a protocol for Israel to provide strike coordinates to clearing agencies to mitigate post-conflict civilian harm. However, applying this “day after” obligation to strikes deep inside Iranian territory presents unprecedented logistical and legal hurdles.
“I do not know whether or where such munitions are being used by the IDF in Iran,” Libman said, noting that while media reports suggest that some military targets are far from civilian centers, the legality remains case-specific.
“The key legal question is how, where, and against which targets they are used, taking into account the specific characteristics of the weapons involved.”
The Winograd report previously noted that the effectiveness of cleanup efforts depends entirely on operational discipline at the time of firing. In the context of a high-intensity war against a hostile state with no diplomatic channels, the feasibility of mapping and sharing strike data – a core requirement of customary law – remains unclear.
Ultimately, the strategic advantage of area-saturation weapons must be weighed against the risk of losing the legal high ground. As Libman concluded, neither side is absolutely prohibited from using these weapons, but the legality of their use remains a question of “taking into account the specific characteristics of the weapons involved” and the environment in which they land.