Pentagon officials have said the United States used bunker buster bombs to attack Iran's Fordow nuclear facility on Sunday.

At a news conference in Washington, US Defense Secretary Pete Hegseth said: "It was an incredible and overwhelming success. The order we received from our commander in chief was focused, it was powerful and it was clear. We devastated the Iranian nuclear program."

They used the GBU-57 Massive Ordnance Penetrator. It is designed to attack deeply-buried sites and hardened bunkers and tunnels.

US Joint Chiefs of Staff Chairman Dan Caine said that the lead B2 aircraft dropped two of the weapons on the first of several points at Fordow at approximately 6:40 p.m. Eastern Standard Time on Saturday, or 2:10 a.m. on Sunday local Iran time.

He said the remaining bombers then hit their targets as well, with a total of 14 of the bunker buster weapons used. Caine said that Tomahawk missiles were the last to strike at the Isfahan facility.

Hegseth said the operation did not target Iranian troops or civilians. He added the mission "has not been about regime change" in Iran.