Breaching the Iron Dome: the Iranian cluster bombs bypassing Israeli air defences
Gleaming trails of bomblets in night sky have become familiar to Israelis as Tehran exploits apparent vulnerability
On 5 March, a post appeared on the X account of Iran’s late supreme leader, Ali Khamenei, managed by his staff after he was killed in an Israeli airstrike on 28 February. The tweet featured a stark piece of propaganda: a gleaming, oversized missile arcing across the sky as a city below is engulfed in flames. The caption read: “Khorramshahr moments are on the horizon.”
The Khorramshahr missile, Iran’s most advanced ballistic missile, is believed to be capable of carrying a cluster warhead dispersing up to 80 submunitions. Since that post, it has come to loom large in Israeli threat assessments, a persistent concern for a country equipped with a multi-layered missile defence system that is widely regarded as the world’s most sophisticated.
The latest attack using cluster munitions occurred on Sunday, when an Iranian ballistic missile struck central Israel, injuring 15 people.
According to the Israel Defense Forces, roughly half of the missiles launched from Iran since the escalation have carried cluster warheads.
The Guardian, which reviewed the impact of dozens of Iranian strikes alongside statements from Israeli officials, has identified at least 19 ballistic missiles carrying cluster warheads that penetrated Israeli airspace and struck urban areas since the beginning of the war with Iran on 28 February. Those attacks have killed at least nine people and wounded dozens, reflecting a broader shift in Iran’s tactics that appears to have exposed a vulnerability in Israel’s air defences. Since the start of the war, Iran’s cluster munitions – which disperse dozens of bomblets mid-air – have tested Israel’s highly advanced, multi-tier missile defence network, including Iron Dome, which is designed to counter threats across ranges, altitudes and speeds, exposing gaps that interception alone has struggled to close.
“Intercepting cluster munitions is fundamentally more difficult than stopping unitary missiles due to several technical shifts in the engagement profile,” said Tal Inbar, a missile expert who consults for Israeli defence companies. “To be effective, an interceptor must strike the carrier vehicle before dispersal.”
Cluster bombs are designed to release dozens of smaller bombs, called submunitions, over a wide area. Smaller munitions do not always explode immediately, posing a future risk to civilians. When cluster munitions are suspected, military teams sweep wide areas in coordinated searches, before police bomb-disposal units move in to neutralise unexploded bomblets.
To limit the damage, weapons experts say cluster munitions must be intercepted as far from their target as possible – ideally outside the atmosphere. Once the submunitions are released mid-air, interception becomes, even with the most sophisticated missile defence systems, virtually impossible.
Cluster munitions are inherently indiscriminate, and their use in populated areas is prohibited under international humanitarian law. While the 2008 convention on cluster munitions bans them for signatory states, neither Israel nor Iran are party to it.
Amnesty International condemned Iran’s use of cluster munitions last June – during its 12-day war with Israel – as a “flagrant violation” of international law. The organisation accused Israel of similar breaches over its use of the weapons in Lebanon in 2006. Israel has acknowledged deploying cluster munitions in the past, maintaining that it does so in line with international law, but described Iran’s use of bomblets towards a centre of mass population as “a war crime by the Iranian regime”.
Since early March, videos have circulated online showing cluster munitions descending as dozens of bright points of light, slicing through the night sky over greater Tel Aviv before impact. The clips have, in their own way, become the defining visual shorthand of the war with Iran for Israeli civilians.
Two such strikes in the early morning of 18 March killed a couple in their 70s in Ramat Gan, just east of Tel Aviv, and a 30-year-old Thai worker in Adanim, central Israel.
Israeli officials say that even a direct intercept of a ballistic missile, before its warhead splits and scatters its payload, does not always ensure the submunitions are fully neutralised.
Iran’s strategy also appears to carry a more pragmatic aim: beyond slipping smaller payloads through Israel’s air defences, the use of cluster munitions may be designed to drain interceptor stocks – forcing Israel to expend dozens of missiles to neutralise a single incoming threat.
Inbar also points to a significant economic constraint: intercepting Iranian missiles carrying cluster munitions is simply not cost-effective, as it would “require using expensive interceptors to target each individual submunition”.
Speculation is mounting that interceptor supplies may be under strain, though the true size of Israel’s stockpile remains a closely guarded secret.
Israel’s military says it has destroyed more than 70% of Iran’s ballistic missile launchers, adding that they had nearly achieved total control over Iranian airspace.
Yet Tehran still manages to breach the Israel’s skies.
Over the weekend, Iranian ballistic missile barrages wounded nearly 200 people in southern Israel, striking the cities of Arad and Dimona after air defence systems failed to intercept at least two projectiles.
Meanwhile, the unrelenting blare of sirens – sending Israelis scrambling for shelter at all hours – and the increasing deployment of cluster munitions are deepening a sense of fatigue, with many now quietly asking how much longer the war can go on, and to what end.
A Guardian investigation last year found evidence of Israel having used cluster munitions in Lebanon during its war with Hezbollah which started in October 2023. Images reviewed by multiple arms experts identified remnants of at least two types of Israeli weapons in areas south of the Litani River.
The Guardian does not have information about the strikes the shells were used in, as the remnants were found after the fact.