Trump gave final go-ahead for Iran attack hours before bombs fell

“The goal was to create a situation when everyone wasn’t expecting it," said a senior administration official.

His order to the military to proceed unleashed a military operation that has been the focus of top-secret planning. Within hours U.S. B-2 bombers penetrated Iranian airspace and dropped half a dozen bunker bombs on Iran’s underground nuclear facility at Fordow. U.S. attack submarines launched Tomahawk cruise missiles against sites in Isfahan and Natanz.

In a White House address Saturday night, Trump called the attacks “a spectacular military success" that left Iran’s nuclear sites “completely and totally obliterated."

But key questions remain unknown, including whether the Iranian program was fully destroyed and whether Iran will respond with its own attacks on the U.S. or its allies—or possibly try to shut down oil exports through the Strait of Hormuz.

The Atomic Energy Organization of Iran vowed Saturday not to give up its efforts. The organization “won’t allow the progress of this national industry—built on the blood of nuclear martyrs—to be halted," it said in a statement.

The Fordow fuel enrichment facility in Iran.

U.S. Special Envoy Steve Witkoff has been authorized to talk with the Iranians, as Trump tried to keep open the long-shot possibility of some sort of diplomatic understanding that could quiet the region.

A U.S. official said the Trump administration had reached out to Iran to make clear the attack was a one-off assault, not the start of a regime-change war.

The decision to attack came after weeks of White House deliberations, closely held military preparations and direct coordination with Israeli Prime Minister Benjamin Netanyahu, who had launched a similar sudden attack on Iran a week earlier.

But Trump seemed conflicted about whether to proceed with the operation over the past week. His advisers also worried about getting pulled into a Middle East conflict despite the frustrations with the diplomatic track aimed at getting Iran to halt its uranium enrichment.

In a Tuesday meeting in the Situation Room, Trump approved of plans to strike Iran but withheld a final order, giving time to assess once more if Iran would be willing to entirely end its enrichment of nuclear fuel.

“There was real debate earlier in the week about what we should do," said the senior official. “But Trump signaled on Tuesday he was leaning toward going forward, so that changed everything."

Trump also wanted to create uncertainty about his intentions—and his timeline. The White House said Thursday Trump would give Iran up to two weeks to show its interest in a diplomatic resolution to the crisis. Only a day later he hinted that his patience was wearing out.

“We’re going to see what that period of time is, but I’m giving them a period of time, and I would say two weeks would be the maximum," he told reporters, adding that he still viewed himself as a peacemaker.

Trump made the decision to go ahead with the operation after Iran continued to rebuff his demand to give up its uranium enrichment and Israel paved the way with more than a week’s worth of strikes on Iran’s nuclear infrastructure and air defenses.

In his Saturday night address, Trump said that his target was Iran’s three principal nuclear sites—Fordow, Natanz and Isfahan—and wasn’t aimed at Iran’s leaders.

President Trump holding a meeting in the Situation Room Saturday, in this photo released by the White House.

The White House released photos of Trump wearing a red Make America Great Again hat with his national-security team in the Situation Room Saturday, where they received updates on the attack as it unfolded.

Air Force Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, was among those flanking the president around the table. Caine was a leading architect of the plans to strike Iran, U.S. officials and people familiar with the deliberations said.

Trump spoke with Netanyahu just after the operation, and the Israeli leader was “incredibly grateful," the senior official said.

Trump vowed to carry out additional strikes if Iran lashed out at U.S. forces in the region and balked at diplomatic efforts to establish a peace.

“Future attacks will be far greater and a lot easier," he warned. “There will be either peace or there will be tragedy for Iran far greater than we have witnessed over the last eight days."

The Israeli Air Force attacked Iranian warships and weapons storage facilities at the Iranian port of Bandar Abbas on Saturday, a military action that appeared to have been intended to blunt Tehran’s ability to retaliate in the Persian Gulf.

Trump said Saturday that the strikes had been closely coordinated with Israel. But the U.S. role changed dramatically over the following weeks.

On June 9, Netanyahu said he was preparing strikes and intended to move forward with an assault. Trump replied he wanted to see diplomacy with Tehran play out a little longer, according to U.S. officials.

Three days later, Trump and Netanyahu spoke again, only this time the Israeli leader made clear he was going to launch a campaign against Iran imminently. The 60-day deadline Trump had initially set for a diplomatic accord had passed, and Israel could wait no longer, Netanyahu said, according to officials familiar with the call.

Trump responded that the U.S. wouldn’t stand in the way, according to administration officials, but emphasized that the U.S. military wouldn’t assist with any offensive operations.

As the bombs started falling that June 12 evening in Washington, Secretary of State Marco Rubio released a statement confirming the U.S. played no role in Israel’s unilateral attack. The initial U.S. military role was defensive and focusing on protecting Israel against Iranian drone and missile attacks.

As the success of Israel’s opening salvos became clear, Trump started to claim credit for enabling the operation with U.S. weapons and saying the strikes could ultimately help compel Iran to make a deal.

Over the following days, Trump held lengthy discussions with key aides about his options, ranging from leveraging Israeli strikes to compel Iran to negotiate its nuclear program away to authorizing American attacks on Iranian nuclear facilities.

After Trump made the final call Saturday in New Jersey, B-2 stealth bombers dropped six 30,000 pound bunker busting bombs on Fordow. More than two dozen cruise missiles were fired by U.S. submarines at Natanz and Isfahan, two other sites where Iran has carried out nuclear work and enriched uranium.

“We won’t know for sure until the morning what was taken out, but our belief is that we took out everything we wanted to," said the senior official.

Write to Michael R. Gordon at michael.gordon@wsj.com, Josh Dawsey at Joshua.Dawsey@WSJ.com and Alexander Ward at alex.ward@wsj.com