What is the ‘Mother of All Bombs’ US could use in Iran?

What Happened

US military planners are reportedly considering using the GBU-43/B Massive Ordnance Air Blast Bomb (MOAB) against Iran's energy infrastructure and nuclear sites if President Donald Trump orders renewed combat operations, according to US officials cited by CNN. The MOAB carries about 8,500kg of high explosives, weighs 9,800kg, and has been used in combat only once: a 2017 US strike on an Islamic State Khorasan Province cave-and-tunnel complex in Afghanistan. Afghan authorities claimed 94 ISKP fighters were killed and no civilians were harmed, while unconfirmed local reports described civilian casualties and destroyed homes.

Key Actors

Why It Matters

Deploying the largest non-nuclear bomb in the US arsenal would mark a major escalation in the US-Iran standoff, extending military pressure onto Iranian territory and nuclear facilities. However, officials familiar with military planning told CNN and Al Jazeera that the MOAB would be unlikely to achieve the stated US goal of destroying Iran's nuclear capabilities, and experts Magnier and Abu Zeid said the weapon is not designed to penetrate deeply buried fortified sites like Fordow or Pickaxe Mountain. Magnier called the proposal "political theatre," underscoring the risk of a spectacular strike with limited strategic gain.

Watch For

Watch for whether the White House or Pentagon formally confirms or denies the reported planning, any forward deployment of C-130 Hercules aircraft capable of carrying the MOAB to bases within range of Iran, and statements from Iran's Foreign Ministry or IRGC responding to the reports. If a strike occurs, monitor IAEA reports or satellite imagery on the condition of the Fordow Fuel Enrichment Plant and the Pickaxe Mountain site, as well as any Iranian military or diplomatic response.