President Donald Trump said today he would not waive sanctions on Iran by a deadline Saturday, effectively pulling out of the Iran deal.

“I am announcing today that the United States will withdraw from the Iran nuclear deal,” Trump said, speaking at the White House on May 8. “In a few moments, I will sign a presidential memorandum to reinstate nuclear sanctions on the Iranian regime.”

The sanctions Trump will reinstate target countries, businesses and individuals that deal with Iran’s financial system.

Trump’s decision comes after a full-court press by three European nations also party to the 2015 deal not to pull out. Over recent weeks, French President Emmanuel Macron, German Chancellor Angela Merkel and British Foreign Secretary Boris Johnson have visited Washington to try and persuade Trump to stay in the deal.

The deal swaps sanctions relief for Iran’s rollback of its nuclear program. Trump had said he might stay in the deal if it could be renegotiated to remove “sunset” clauses that allow Iran to resume some enrichment of fissile material within a decade. He also wants a tougher inspections regime and to roll a missile-testing ban into the deal.

European allies said reopening the deal now, particularly in relation to the sunset clauses, was impossible, especially given the adamant opposition of the other parties: Iran, Russia and China.

Instead, they countenanced increasing pressure on Iran in other arenas, including new sanctions targeting its missile testing, and then committing to pressure on Iran as the sunset clauses loomed closer to extend bans on enrichment.

Trump rejected those overtures. “This was a one-sided deal that should have never ever been made,” he said.

Israel and Saudi Arabia, by contrast, have been U.S. allies pressing for a pullout from the deal. Israeli Prime Minister Benjamin Netanyahu last week unveiled documents showing that, before the 2015 deal, had hidden the breadth of its nuclear weapons development. Trump credited Netanyahu’s presentation in making his decision. “Today we have definitive proof that this promise was a lie,” he said, referring to Iran’s pledge to roll back the agreement.

“It is clear to me that we cannot prevent an Iranian nuclear bomb under the decaying and rotten structure of the current agreement,” he said. “The Iran deal is defective at its core.”

It’s not clear what happens going forward. The Trump administration would have to put in place staff and mechanisms to monitor compliance with U.S. sanctions, a process that could take months, giving some leeway to renegotiate a deal. On the other hand, simply announcing the reimposition of sanctions is likely to have an inhibitive effect on doing business with Iran, effectively crippling it almost immediately.