31MAY

Iran cluster warhead hits three cities

2 min read

09:14UTC

The first confirmed cluster-warhead ballistic missile in this conflict turned three cities into area targets on the same day Israel's missile shield neared zero.

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ConflictDeveloping

Key takeaway

Iran is matching new weapons to Israel's defence gap, turning each missile into an area threat.

A ballistic missile carrying a cluster-bomb warhead struck central Israel on 31 March, scattering submunitions across Bnei Brak, Ramat Gan, and Petah Tikva. ¹ Six people were lightly injured. It was the first confirmed use of a cluster warhead on a ballistic missile in this conflict.

Cluster munitions scatter bomblets across a wide area. Against urban targets, they bypass the point-defence logic of interceptors: even a successful interception may not catch every submunition. The tactical shift suggests Iran is adapting to the interception window that remains before Arrow-3 stocks run out entirely. The USS Tripoli arrived days ago with 3,500 Marines , confirming that Tehran's intelligence services have demonstrated awareness of coalition planning. The cluster warhead's timing, coinciding with RUSI's projected Arrow-3 exhaustion, may reflect similar intelligence-driven calibration.

The three cities hit sit in the Greater Tel Aviv area, the densest urban corridor in Israel. If cluster warheads become standard payload on Iranian medium-range missiles, each launch becomes an area-wide threat rather than a single-point strike. The multiplication effect on civilian risk is substantial. Israel's 6,131 hospitalisations since 28 February already exceed total casualties from the entire 2006 Lebanon War. Undefended cluster warhead strikes would accelerate that count sharply.

Deep Analysis

In plain English

A cluster bomb is a weapon that opens in mid-air and releases dozens or hundreds of smaller bomblets over a wide area, rather than hitting one point. Iran put this type of warhead on a ballistic missile and fired it at central Israel for the first time. Six people were lightly injured this time. The worry is what happens when Israel's missile defence system, which intercepts incoming missiles, runs out of interceptors. RUSI projected that might happen by end of March. If the shield is exhausted and these area-effect weapons keep arriving, they land across entire city blocks rather than one building. That changes the casualty risk from dozens to potentially hundreds per strike.

Deep Analysis

Root Causes

GPS jamming across both Hormuz and Bab al-Mandeb has degraded missile accuracy for both sides. Iran's shift to cluster warheads bypasses the precision problem: area-effect weapons achieve their tactical purpose without requiring a direct hit.

Arrow-3 depletion creates a window of opportunity. Against an undefended target, even a conventional warhead lands with certainty. A cluster warhead against a partially defended target increases the probability that at least some submunitions reach civilians even if the main body is intercepted. This is military adaptation to a specific defence gap rather than an arbitrary escalation.

Iran's IRGC Aerospace Force has faced internal criticism over mismanagement and near-suicidal launch conditions . Switching to a weapon that does not require precision reduces the operational demand on crews while maintaining psychological pressure on Israeli urban populations.

What could happen next?

Risk
If cluster warheads become standard Iranian payload, each missile launch becomes an area-wide threat rather than a single-point strike, multiplying civilian casualty risk in any city targeted.
Immediate · 0.8
Consequence
Even partially successful interceptions may not catch all submunitions, reducing the practical effectiveness of remaining missile defence assets.
Immediate · 0.85
Precedent
First confirmed use of cluster warheads on ballistic missiles in this conflict establishes a qualitative threshold that may prompt Israeli or US pressure for expanded rules of engagement.
Short term · 0.7
Risk
Post-conflict unexploded submunitions in urban Israeli areas will cause civilian casualties for years after any ceasefire.
Long term · 0.9

Source Landscape

This story draws on centre-left-leaning sources from Israel

Israel

Primary parallel: US use of cluster munitions in the 2003 Iraq invasion and Israeli use in the 2006 Lebanon War both generated significant post-conflict civilian casualties from unexploded bomblets. In south Lebanon, UNICEF documented 1 million unexploded submunitions covering 45 sq km after 2006. Urban use dramatically amplifies this risk.

Counter-parallel: Iraqi Scud use against Israeli cities in 1991 employed conventional warheads and did not escalate to area-effect weapons. Israel absorbed the strikes without retaliating directly. That restraint option is functionally unavailable with cluster warheads given the expanded civilian risk profile.

Consensus view: RUSI's Justin Bronk and Chatham House's Emily Hawthorne both assess the cluster warhead as a doctrinal escalation. Iran is compensating for GPS jamming degrading missile accuracy by switching to area-effect weapons that do not require precision. The timing, coinciding with projected Arrow-3 exhaustion, suggests deliberate calibration rather than operational opportunism.

Counter-view: Iranian military analyst Hamid Mousavi argues this reflects legitimate military doctrine under duress: cluster munitions are not banned under international law for non-signatories to the Convention on Cluster Munitions. Neither Iran nor the US are signatories. Tehran frames it as proportionate response to bunker-busters on civilian-adjacent ammunition depots.

Key tension: Whether this establishes a new Iranian standard payload for all future launches, or remains a one-off test ahead of confirmed Arrow-3 exhaustion.

Sources:Times of Israel

Mentions:Arrow-3 →RUSI →Lebanon →USS Tripoli →Bnei Brak →Ramat Gan →

First Reported In

Update #53 · Trump drops Hormuz goal; toll becomes law

Times of Israel· 31 Mar 2026

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Causes and effects

Caused by

10,000 targets struck; 92% of navy gone

Iran's cluster-warhead missile launch against Israeli cities is a direct retaliatory escalation following the overnight Isfahan bunker-buster strikes.

Occurred 27 Mar 2026

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This Event

Iran cluster warhead hits three cities

Cluster warheads on ballistic missiles shift the threat from single-point strikes to area-wide civilian danger, arriving as upper-tier interceptors approach exhaustion.

Different Perspectives

Human rights monitors (Hengaw, Amnesty International, Iran HRM)

Monitors documented a second death sentence for Zahra Tabari, 68, reported cemetery record deletions at Behesht-e Zahra, and a poll showing 81.5% of medical residents want to emigrate, against a background of 200+ confirmed executions since February. Iran's security courts operate at uninterrupted wartime tempo regardless of the diplomatic track.

Pakistan (mediator)

Islamabad carried Trump's revised MOU demanding HEU destruction to Iranian negotiators, formally inheriting the role of sole active mediator after Oman's forced withdrawal. Pakistan lacks Oman's banking infrastructure for frozen-asset routing and carries its own regional stakes, making it a less structurally neutral broker.

Kuwait

Kuwait intercepted Iranian missiles and drones for a second time in days on 1 June, with air-raid sirens sounding nationwide, after invoking Article 51 self-defence on 28 May following the Ali Al Salem ballistic-missile strike. The repeated interceptions test whether Kuwait's domestic politics can sustain hosting US forces as a de facto co-belligerent.

China (PRC)

Beijing sent scholars to Shangri-La rather than its defence minister and addressed Taiwan without mentioning Iran, maintaining bilateral energy corridor protection with Tehran while refusing diplomatic exposure at multilateral forums. Trump barred China as an HEU custodian on 27 May, removing Beijing from the deal architecture while China continues supplying DPI hardware that caps Iran's internet.

Lloyd's of London / war-risk underwriters

Lloyd's held its Hormuz war-risk designation at $10-14 million per voyage while Brent recovered to $93.91, maintaining the structural divergence from futures pricing that has persisted since late May. Underwriters require a UN Security Council resolution or government certification letter, not diplomatic optimism.

Gulf Cooperation Council states (Saudi Arabia, UAE, Bahrain, Qatar)

Five Gulf states wrote to the IMO on 21 May rejecting Iran's PGSA transit authority over international waters; Saudi Arabia and the UAE have not confirmed participation in the European Hormuz mission. The GCC is navigating between US security guarantees and exposure to Iranian fire, with no Gulf state formally co-belligerent except Kuwait.