The US Air Force ordered new heavy anti-bunker bombs GBU-57 from Boeing.

The US Air Force has entered into a new contract with Boeing Corporation for the production of heavy GBU-57 bunker-busting bombs (MOP), designed to destroy fortified underground targets. These munitions should be added to the arsenal after attacks on Iranian nuclear infrastructure in June 2025.

The exact number of bombs remaining in the US arsenal after the strikes on Iran has not been disclosed.

The contract was awarded to Boeing without a tender. The Air Force said attempting to use other suppliers would have resulted in “unacceptable delays” and degraded operational readiness.

In June, The New York Times quoted an American official as saying that B-2 bombers dropped 12 GBU-57 bombs on the Fordo nuclear site and two more such bombs were dropped on the Natanz site.

MOP production is a complex and lengthy process: it can take 18-36 months to manufacture and bring it to combat readiness, and the first deliveries under the new contract are expected to begin in January 2028.