What are the US' bunker-buster bombs it used to strike Iran?

22 June 2025, 08:41

The US stunned the world on Saturday night by striking three Iranian nuclear facilities with a dozen "bunker buster bombs". Here's what you need to know about the American weapon.

The 30,000lb bunker busters were dropped from the US' B-2 stealth bombers - the only aircraft capable of carrying the only weapons that can target heavily fortified nuclear sites.

The weapons are designed to destroy heavily protected sites, including bunkers deep underground where a typical bomb can't reach.

They can bury themselves deep into the ground before detonating, providing more explosive force when they are set off.

The GBU-57 MOP (Massive Ordnance Penetrator) bunker buster was the largest kind used in the attacks overnight weighing some 13.5 tonnes.

Read more: READ IN FULL: Donald Trump's address to America after US attacks on Iran's nuclear sites

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Experts say the GBU-57 is capable of causing significant damage and perhaps irreparable destruction to even Iran's most protected sites.

It is believed tone capable of penetrating up to 60 metres below the surface.

It is 20 feet long and had reportedly never been used in combat before this.

As three of Iran’s nuclear enrichment sites - Fordow, Natanz and Isfahan - are built deep underground, Israel was reliant on the American weapons to properly scupper the Islamic Republic's potential nuclear capabilities.

Iran's most fortified and strongest -protected nuclear site is called Fordo and is buried deep inside a mountain. It is not believed to have been targeted on Saturday.

Aaron David Miller, of the Carnegie Endowment for International Peace think tank, said: "[Israel] can't destroy Tehran's program on their own.

"But if they stop and it survives, this will be viewed as a defeat."

Not only does Israel lack the bombs, but it also lacks the B-2 stealth bombers needed to carry them.

Trump surprised the world a little before 8 p.m. Saturday by announcing on Truth Social that he had given the go-ahead to attack Iran, using 12 massive 30,000-pound 'bunker buster' bombs and 30 Tomahawk missiles to destroy Fordow, Natanz, and Esfahan.

In what is the most consequential decision of Mr Trump’s presidency so far, the assault signals a significant escalation in the conflict with Tehran.

Pressure had been mounting on the US to intervene in the escalating conflict in support of Israel, and to force Iran’s leaders to end its nuclear programme.

Trump told reporters on Friday that he was not interested in sending ground forces into Iran, saying it's "the last thing you want to do."

He had previously indicated that he would make a final choice over the course of two weeks, a timeline that seemed drawn out as the situation was evolving quickly.

In a national address following the attack, Mr Trump threatened further strikes if the country did not immediately make peace.

He called on Iran to bring swift peace with the US, or face more strikes dealt with “speed” and “precision”. "This cannot continue. There will be either peace or there will be tragedy for Iran, far greater than we have witnessed over the last eight days," he said.

"Iran's nuclear enrichment facilities have been completely and totally obliterated," Trump said.

"Iran, the bully of the Middle East, must now make peace. If they do not, future attacks would be far greater and a lot easier." "Remember, there are many targets left," Trump said.