U.S. President Donald Trump struck a blow against the 2015 Iran nuclear agreement on Friday in defiance of other world powers, choosing not to certify that Tehran is complying with the deal and warning he might ultimately terminate it.

Trump announced the major shift in U.S. policy in a speech in which he detailed a more aggressive approach to Iran over its nuclear and ballistic missile programs and its support for extremist groups in the Middle East.

He accused Iran of “not living up to the spirit” of the nuclear agreement and said his goal is to ensure Tehran never obtains a nuclear weapon, in effect throwing the fate of the deal to Congress.

He singled out Iran’s Islamic Revolutionary Guard Corps for sanctions and delivered a blistering critique of Tehran, which he accused of destabilizing actions in Syria, Yemen and Iraq.

“We will not continue down a path whose predictable conclusion is more violence, more terror and the very real threat of Iran’s nuclear breakout,” Trump said.

Trump’s hardline remarks drew praise from Israel, Iran’s arch-foe, but was criticized by European allies.

The move by Trump was part of his “America First” approach to international agreements which has led him to withdraw the United States from the Paris climate accord and the Trans-Pacific Partnership trade talks and renegotiate the North American Free Trade Agreement with Canada and Mexico.

His Iran strategy angered Tehran and put Washington at odds with other signatories of the accord - Britain, France, Germany, Russia, China and the European Union - some of which have benefited economically from renewed trade with Iran.

Responding to Trump, Iranian President Hassan Rouhani said on Friday on television that Tehran was committed to the deal and accused Trump of making baseless accusations.