President Donald Trump said Saturday that the U.S. military struck three sites in Iran, directly joining Israel ’s effort to decapitate the country’s nuclear program in a risky gambit to weaken a longtime foe amid Tehran’s threat of reprisals that could spark a wider regional conflict.

The decision to directly involve the U.S. comes after more than a week of strikes by Israel on Iran that have moved to systematically eradicate the country’s air defenses and offensive missile capabilities, while damaging its nuclear enrichment facilities. But U.S. and Israeli officials have said that American stealth bombers and a 30,000-lb. bunker buster bomb they alone can carry offered the best chance of destroying heavily-fortified sites connected to the Iranian nuclear program buried deep underground.

“We have completed our very successful attack on the three Nuclear sites in Iran, including Fordow, Natanz, and Esfahan,” Trump said in a post on social media. “All planes are now outside of Iran air space. A full payload of BOMBS was dropped on the primary site, Fordow. All planes are safely on their way home.”