US Orders New GBU-57 ‘Bunker Buster’ Bombs Amid Rising Tensions with Iran

Washington: The United States Air Force has placed a contract with aerospace giant Boeing for the supply of GBU-57 Massive Ordnance Penetrator (MOP) “bunker buster” bombs. The move comes as the US seeks to replenish its stockpile following last year’s operation against Iranian nuclear facilities.

During Operation Midnight Hammer in June 2025, the US deployed these bombs against underground nuclear installations in Iran. Designed to penetrate deep into rock and reinforced concrete before detonating, the GBU-57 is regarded as the most powerful non-nuclear bomb in the US arsenal and is typically deployed from the B-2 Spirit bomber.

According to Israeli media reports, the Air Force is issuing a sole-source contract to Boeing to replace the GBU-57s expended during Operation Midnight Hammer. The precise number of bombs ordered, contract value, and delivery schedule have not been disclosed, citing operational security and strategic considerations.

Capabilities of the GBU-57 Bunker Buster
The GBU-57 MOP weighs approximately 14,000 kg, measures 20.5 feet in length, and has a diameter of 31.5 inches. Its warhead contains a combination of AFX-757 and PBXN-114 explosives, totaling around 2,500 kg, and is capable of penetrating up to 200 feet of reinforced concrete.

First developed in the early 2000s, the bomb has undergone continuous upgrades to enhance its accuracy and destructive potential. It uses GPS guidance to target underground bunkers and other heavily fortified installations. During the June 2025 strikes, these bombs were reportedly used against Iran’s Fordow nuclear facility and other subterranean sites, though claims about the exact damage vary.

Rising US-Iran Tensions
Tensions between Washington and Tehran have escalated since early this year. Former President Donald Trump’s interference in Iranian protests and threats of military action triggered heightened hostility, prompting Iran to issue counter-threats. Despite the recent resumption of nuclear talks between the two countries, the risk of military confrontation remains high, fueled by aggressive rhetoric from both sides.

The new order of GBU-57 bombs underscores the US commitment to maintaining strategic capabilities and highlights the fragile state of US-Iran relations.