President Donald Trump on Saturday said the US military had bombed three nuclear sites in Iran, "completely and totally obliterating" Tehran's enrichment capacity.
The development ended days of speculation about whether America would become directly involved in Israel's war against Tehran. Mr Trump said that any retaliation by Iran against the US would be met with overwhelming force.
"Tonight, I can report to the world that the strikes were a spectacular military success," Mr Trump said in a three-minute address to the nation from the White House, flanked by Vice President JD Vance, Defence Secretary Pete Hegseth and Secretary of State Marco Rubio.
"Iran's key nuclear enrichment facilities have been completely and totally obliterated."
Iranian state media, however, said that all three sites had been evacuated and their contents moved before the bombings.
Morteza Heydari, spokesman for the Qom Provincial crisis management department, told the Tasnim news agency that “complete peace prevails in the holy city of Qom and the province".
Earlier, Iran's President Masoud Pezeshkian had said that his country's "response to the continued aggression of the Zionist regime will be more devastating" during a phone call with French President Emmanuel Macron, according to the official IRNA news agency.
Israel had repeatedly called on its ally America to join its war and Mr Trump has said he would not tolerate Iran developing a nuclear weapons programme.
On Saturday, he said he had worked with Israel's Prime Minister Benjamin Netanyahu to co-ordinate the strikes.
"We worked as a team like perhaps no team has ever worked before, and we've gone a long way to erasing this horrible threat to Israel," he said, adding that the action was "the most difficult" and the "most lethal".
Calling Iran "the bully of the Middle East," he said that if peace is not achieved soon, the US would go after other targets.
Earlier on Saturday in a post on Truth Social, Mr Trump said the Fordow, Natanz, and Isfahan nuclear sites had been targeted.
“All planes are now outside of Iran air space. A full payload of bombs was dropped on the primary site, Fordow.”
He also posted a screenshot of a social media account that said: "Fordow is gone."
The US has bunker-busting bombs designed to destroy hardened facilities buried deep underground, including Fordow, which is in a mountain.
Mr Trump went on to call for peace and praise the "great American warriors".
The strikes came after the US President had voiced deepening frustration with Tehran over its failure to come to a deal on putting limits on its nuclear programme.
"This is an historic moment for the United States of America, Israel, and the world. Iran must now agree to end this war," he said in a different post.
B-2 Spirit bombers were reportedly used in the strikes. The stealth jets can carry the GBU-57 Massive Ordnance Penetrator. It weighs 13,600kg and can purportedly go through up to 100 metres of reinforced concrete. Its conventional explosive power is close to that of an atom bomb.
The US has previously lent support to Israel's defence in the conflict, with Prime Minister Benjamin Netanyahu thanking Mr Trump for "support in defending Israel's skies".
Mr Trump spoke to Mr Netanyahu after the strikes, AFP reported, citing a senior White House official.
The US also "gave Israel a heads-up before the strikes," the official said.
America's attack on Iran comes despite deep divisions among Mr Trump's Republicans over whether the US should become involved in another Middle East conflict.
The President campaigned on ending costly foreign wars and vowed to bring the Russia-Ukraine and Israel-Gaza wars, which preceded his term, to a swift end.
"There would not be bombs falling on the people of Israel if Netanyahu had not dropped bombs on the people of Iran first," Marjorie Taylor Greene, a leading Make America Great Again Republican isolationist congresswoman, wrote in a post on X.
"Israel is a nuclear armed nation. This is not our fight. Peace is the answer."
Democratic House minority leader Hakeem Jeffries criticised the strike.
“President Trump misled the country about his intentions, failed to seek congressional authorisation for the use of military force and risks American entanglement in a potentially disastrous war in the Middle East," Mr Jeffries said in a statement.
UN Secretary General Antonio Guterres said he was gravely alarmed by the US strikes.
"This is a dangerous escalation in a region already on the edge – and a direct threat to international peace and security," he said in a statement.
"There is a growing risk that this conflict could rapidly get out of control – with catastrophic consequences for civilians, the region, and the world."
Some Republican leaders, however came out strongly in support of Mr Trump's decision, with House Speaker Mike Johnson saying that the President "gave Iran’s leader every opportunity to make a deal, but Iran refused to commit to a nuclear disarmament agreement".
And the head of the Senate Armed Services Committee, Senator Roger Wicks, said "our commander-in-chief has made a deliberate - and correct - decision to eliminate the existential threat posed by the Iranian regime".
Senator Tom Cotton said Mr Trump "made the right call and the ayatollahs should recall his warning not to target Americans".
