Iran says it has plans to respond to any move by US President Donald Trump on the 2015 nuclear agreement and the US would regret a decision to exit the accord, as France's president warned such a move could lead to war.
Trump says that unless European allies rectify "flaws" in Tehran's deal with world powers by May 12, he will refuse to extend US sanctions relief for Iran.
"We have plans to resist any decision by Trump on the nuclear accord," Iran's President Hassan Rouhani said in a speech carried live by state television.
"Orders have been issued to our atomic energy organisation ... and to the economic sector to confront America's plots against our country," Rouhani told a rally in northeast Iran on Sunday.
"America is making a mistake if it leaves the nuclear accord," Rouhani said.
In a magazine interview, French President Emmanuel Macron warned a decision by Trump to withdraw could lead to war.
"We would open the Pandora's box. There could be war," Macron told German weekly magazine Der Spiegel, adding "I don't think that Donald Trump wants war." Macron urged Trump not to withdraw when he met him in Washington late last month.
Britain, France and Germany remain committed to the nuclear accord but, in an effort to keep Washington in it, want to open talks on Iran's ballistic missile program, its nuclear activities beyond 2025 - when key provisions of the deal expire - and its wars in Syria and Yemen.
"We will not negotiate with anyone about our weapons and defences, and we will make and store as many weapons, facilities and missiles as we need," Rouhani said, reiterating a rejection by Iranian leaders of talks on Iran's missile program which Tehran says is defensive.
"You (US) should know that you cannot threaten this great nation because our people withstood eight years of ... defence (in the war with Iraq)," Rouhani said in another speech during his visit to Razavi Khorasan province.
"We want to preserve our peaceful nuclear technology for electricity, medicine, agriculture and health... and we do not seek to threaten the world or the region," Rouhani said.
Meanwhile Israeli Prime Minister Benjamin Netanyahu on Sunday stepped up his calls to end the Iranian nuclear deal.
In a briefing to foreign reporters, The Associated Press reports, Netanyahu said "a deal that enables Iran to keep and hide all its nuclear weapons know-how, is a horrible deal".