The head of Iran’s Atomic Energy Organization, Ali Akbar Salehi, said Sunday that if Iran left the seven-power deal designed to prevent it from making nuclear weapons, it could begin enriching uranium to weapons-grade within four days.

Salehi, who is also the nation’s vice president, was quoted by state television as saying if Iran found the nuclear deal was not protecting its interests, “we can re-start 20 percent enrichment in four days. The other side knows what that means.”

He also said Iran is committed to giving International Atomic Energy Agency inspectors access to its nuclear facilities only as long as the nuclear deal remains in force.

Under the deal, IAEA inspectors are granted access to Iranian nuclear facilities to verify that Tehran is abiding by terms of the July 2015 agreement signed by Iran and six major powers — Britain, China, France, Germany, Russia and the United States. By signing the accord formally known as the Joint Comprehensive Plan of Action, Iran pledged to curb activities such as uranium enrichment in return for the lifting of a raft of economic sanctions.

In a related development, the Iranian Foreign Ministry on its website dismissed U.S. President Donald Trump’s claim on Friday that Iran is failing to abide by the nuclear deal, and called the U.S. government an “unreliable” negotiating partner.

“The claim by the president of United States regarding Iran’s non-compliance has no international relevance or credibility, since the IAEA, as the sole authority to conduct such monitoring and verification, has repeatedly confirmed Iran’s full compliance with its commitments under the JCPOA,” it said.

On Friday, Trump vowed not to continue certifying that Iran is complying with the nuclear agreement, and threatened he might terminate the deal at any time.

Trump said Iran’s nuclear and ballistic missile programs and its support for extremist groups in the Middle East demanded a more hard-line stance.

In its response, the Foreign Ministry said Iran would not be the first party to withdraw from the deal. But it also said if Iran’s rights and interests in the deal were not respected, “it will stop implementing all its commitments and will resume its peaceful nuclear program without any restrictions.”

Foreign Minister Javad Zarif said Saturday night that he will lodge an official complaint with the Joint Commission in Vienna over Trump’s “anti-Iran” tirade on Friday.

Trump’s remarks violated articles 26, 28 and 29 of the Joint Comprehensive Plan of Action, and by Monday “we will write a letter to the Joint Commission,” which is responsible for addressing the concerns and complaints of the agreement signatories, Zarif said on state-run television.

“We won’t let anyone interfere in our missile and defense matters. Our defense is not negotiable,” Zarif said.