"The worst would be that the consequence of this is Iran's exit from the Non-Proliferation Treaty and therefore, ultimately, a drift and a collective weakening," Macron told journalists after an EU summit in Brussels.

Macron said that in a bid to maintain the treaty -- that is meant to limit the spread of nuclear weapons -- he would speak in the coming days to the five members of the United Nations Security Council.

Those talks already kicked off with a call with President Donald Trump on Thursday in which Macron said he informed his US counterparts of contacts Paris had with Tehran in "the last few days and hours".

"Our hope is that there will be a real convergence of views," Macron said, adding that the aim was "that there should be no resumption" of nuclear buildup by Iran.

Iran ratified the nuclear non-proliferation treaty (NPT) in 1970, committing it to declare its nuclear material to the International Atomic Energy Agency.

But it has recently begun preparing the grounds for a possible withdrawal from the treaty, accusing the agency of acting as a "partner" in Israel's "war of aggression".

American B-2 bombers hit two Iranian nuclear sites with massive GBU-57 bunker-buster bombs last weekend, while a guided missile submarine struck a third site with Tomahawk cruise missiles.

Trump himself has called the strikes a "spectacular military success" and repeatedly said they "obliterated" the nuclear sites.

But US media revealed a preliminary American intelligence assessment earlier this week that said the strikes only set back Iran's nuclear program by months -- coverage sharply criticised by Defense Secretary Pete Hegseth and others.