Zarif told reporters in New York that Iran is not seeking to acquire a nuclear bomb, but that Tehran's "probable" response to a US withdrawal would be to restart production of enriched uranium -- a key bomb-making ingredient.

"America never should have feared Iran producing a nuclear bomb, but we will pursue vigorously our nuclear enrichment," added the foreign minister, who is in the United States to attend a UN meeting on sustaining peace.

US President Donald Trump has set a May 12 deadline for the Europeans to "fix" the 2015 agreement that provides for curbs to Iran's nuclear program in exchange for relief from financial sanctions.

Zarif's comments marked a further escalation of rhetoric following a warning earlier this month from Iranian President Hassan Rouhani that Washington would "regret" withdrawing from the nuclear deal, and that Iran would respond within a week if it did.

The fate of the Iran deal will be a key issue during French President Emmanuel Macron's state visit to Washington beginning Monday, followed by talks with German Chancellor Angela Merkel in Washington on Friday.

Zarif said the European leaders must press Trump to stick to the deal if the United States "intends to maintain any credibility in the international community" and to abide by it, "rather than demand more."

The foreign minister warned against offering any concessions to Trump.

"To try to appease the president, I think, would be an exercise in futility," he said.

European leaders are hoping to persuade Trump to save the deal if they, in turn, agree to press Iran to enter into agreement on missile tests and moderating its regional influence in Yemen, Syria and Lebanon.

If the United States buries the deal, Iran is unlikely to stick to the agreement alongside the other signatories -- Britain, China, France, Germany and Russia --- said the foreign minister.

"That's highly unlikely," he said. "It is important for Iran to receive the benefits of the agreement and there is no way that Iran would do a one-sided implementation of the agreement."

Zarif, who will attend a UN meeting on sustaining peace this week, warned of "drastic measures" under discussion in Iran.

He declined to be more specific, pointing to "what certain members of our parliament are saying about Iran's options."