NBC- President Donald Trump is likely to scrap the Iran nuclear deal, French President Emanuel Macron said, adding that he is working on containing the damage with an ambitious new diplomatic framework.

Macron made the comments during a roundtable with reporters Wednesday night on the eve of his trip home following three days of high-stakes meetings with Trump about the thorniest foreign policy issues facing the two leaders.

Macron fielded questions and spoke candidly about what he took away from his meetings with Trump.

Macron said he can't be sure what Trump will do on May 12, the next deadline for the U.S. to recertify Iran�s compliance with the nuclear deal, but he believes Trump will scrap it to satisfy domestic political concerns.

Macron said that during his private Oval Office meeting with Trump on Tuesday, the president�repeated his long-held criticism of the agreement, describing it as "the worst deal ever, it�s a nightmare, it was a catastrophe, and so on and so on."

Macron said he told Trump during their private talks that killing the deal �would open Pandora�s box,� adding: �I don�t think your president wants to make war with Iran.�

The Iran nuclear deal offered Tehran billions of dollars in sanctions relief in exchange for agreeing to curb its nuclear program.

Macron also suggested that Trump's Iran strategy is influenced by what he sees as the result of his hardline tactics toward North Korea.

�His experience with North Korea is that when you are very tough, you make the other side move and you can try to go to a good deal or a better deal," Macron said. "That's a strategy of increasing tension ... It could be useful."

Macron predicted that if the U.S. gets out of the�Joint Comprehensive Plan of Action�� the formal name for the deal between China, France, Germany, Russia, the United Kingdom, the U.S., the European Union and Iran to ensure Tehran's nuclear program remains peaceful � the Trump administration will impose very tough sanctions on Iran, leading to a time of greater tension.

Macron acknowledged that, while he has had talks with Iranian President Hassan Rouhani, he does not know how Iran would respond given deep divisions in the regime.

The French president said his mission was to come up with a diplomatic strategy to contain the damage in the aftermath of an American withdrawal, and he believes his trip to Washington was a success because he began that conversation.

Filling in more details of an ambitious multi-part strategy Macron floated at Tuesday�s White House news conference, the French president said he is trying to create a new, smaller coalition to build on the JCPOA and make the nuclear ban permanent, ban Iran�s ballistic missile program, and contain Iran�s aggression in Syria, ultimately leading to political negotiations to end the civil war.

Macron said he had discussed his ideas with Russian President Vladimir Putin before arriving in Washington, and sees Russia and Turkey as critical to future talks on Syria. He said China, an original signatory to the Iran nuclear deal, did not need to be involved in hypothetical new diplomatic track.

His proposed goals are all aimed at resolving key criticisms Trump has voiced about the more limited scope of the current Iran deal.

Macron has already been followed to Washington by Israel�s hardline Defense Minister, Avigdor Lieberman, who hoped to shore up the administration�s resolve to withdraw from the Iran deal.

He is expected to meet with National Security Adviser John Bolton and Defense Secretary James Mattis.

And on Friday, Germany�s Angela Merkel will meet with Trump for a few hours to add support for Macron's arguments to Trump on Iran, steel and aluminum tariffs and Syria policy.

Trump and Merkel are known to have a difficult relationship, and she is not expected to get the warm welcome or the pomp and circumstance afforded to Macron.