"If the United States withdraws from the nuclear deal, then we will not stay in it," Ali Akbar Velayati, foreign policy advisor to supreme leader Ayatollah Ali Khamenei, was quoted as saying by the state television website.

Trump has threatened to abandon the agreement when it comes up for renewal on May 12, calling it "insane".

Iran has always denied it sought a nuclear weapon, insisting its atomic programme was for civilian purposes.

Velayati warned against any move to try to renegotiate the deal signed by Iran and six world powers in 2015 curbing Tehran's nuclear programme in exchange for sanctions relief.

"Iran accepts the nuclear agreement as it has been prepared and will not accept adding or removing anything," he said.

"Even if countries allied with the United States, especially the Europeans, seek to revise the nuclear agreement... one of our options will be withdrawing from the accord," Velayati added.

Britain, France and Germany -- the three European countries that signed the deal -- have repeatedly tried to persuade Trump not to abandon it.

French President Emmanuel Macron on Wednesday reiterated his commitment to the accord but admitted that it needed strengthening.

"I don't know what the US president will decide on May 12," Macron said during a visit to Sydney.

"I just want to say whatever the decision will be, we will have to prepare such a broader negotiation and a broader deal, because I think nobody wants a war in the region, and nobody wants an escalation in terms of tension in the region," he said.