US forces struck three Iranian nuclear sites in a “very successful attack,” President Donald Trump said on Saturday, adding that the crown jewel of Tehran’s nuclear program, Fordow, is gone.

After days of deliberation, Trump’s decision to join Israel’s military campaign against its major rival Iran represents a major escalation of the conflict.

“A full payload of BOMBS was dropped on the primary site, Fordow,” he said. “Fordow is gone.”

“IRAN MUST NOW AGREE TO END THIS WAR,” he posted.

The Republican president said he will deliver a televised Oval Office address at 10 p.m. EST (0300 GMT).

US B-2 bombers were involved in the strikes, a US official told Reuters, speaking on condition of anonymity.

Reuters had reported earlier on Saturday the movement of the bombers, which can be equipped to carry massive bombs that experts say would be needed to strike Fordow, which is buried under a mountain.

Israel’s public broadcaster Kan cited an Israeli official saying the country was “in full coordination” with Washington on the US attack.

The strikes came as Israel and Iran have been engaged in more than a week of aerial combat that has resulted in deaths and injuries in both countries.

Israel launched the attacks on Iran saying that it wanted to remove any chance of Tehran developing nuclear weapons. Iran says its nuclear program is for peaceful purposes only.

Diplomatic efforts by Western nations to stop the hostilities have been unsuccessful.

In recent days, Democratic lawmakers and some Republicans have argued that Trump must receive permission from the US Congress before committing the US military to any combat against Iran.

Israeli military officials said earlier on Saturday that they had completed another series of strikes in southwestern Iran, having targeted dozens of military targets.

Israel launched attacks on June 13, saying Iran was on the verge of developing nuclear weapons. Israel is widely assumed to possess nuclear weapons, which it neither confirms nor denies.

At least 430 people have been killed and 3,500 injured in Iran since Israel began its attacks, Iranian state-run Nour News said, citing the health ministry.

In Israel, 24 civilians have been killed by Iranian missile attacks, according to local authorities, in the worst conflict between the longtime enemies. More than 450 Iranian missiles have been fired towards Israel, according to the Israeli prime minister’s office.

Israeli officials said 1,272 people have been injured since the beginning of the hostilities, with 14 in serious condition.