U.S. President Donald Trump and French counterpart Emmanuel Macron called for a new deal with Iran Tuesday as Iran has ruled out any changes or additions to the 2015 nuclear deal.

"I think we will have a great shot at doing a much bigger, maybe, deal," Trump said at a news conference with the French president, stressing that any new accord would have to be built on "solid foundations." "They should have made a deal that covered Yemen, that covered Syria," he said, as reported by Agence France-Presse (AFP). "No matter where you go in the Middle East, you see the fingerprints of Iran behind problems."

Macron admitted after meeting Trump that he did not know whether the U.S. president would walk away from the nuclear deal when a May 12 decision deadline comes up. "I can say that we have had very frank discussions on that, just the two of us," Macron told a joint press conference with Trump at his side.

Iran's President Hassan Rouhani poured scorn yesterday on U.S. and European discussions over Tehran's nuclear agreement and dismissed Donald Trump as a "tradesman" who lacked the qualifications to deal with a complex international pact. His comments came after Macron flew to Washington to try to persuade Trump not to scrap the 2015 agreement under which Iran curbed its nuclear program in return for the lifting of sanctions.

Trump and Iran's top diplomat Javad Zarif have traded sharp warnings, with Trump threatening "bigger problems" than ever if Tehran restarts its nuclear program. Foreign Minister Mohammad Zarif put the president on notice, telling the Associated Press if the U.S. pulls out of the nuclear deal, Iran "mostly likely" would abandon it, too.

In a wide-ranging interview Tuesday, Zarif said a U.S. withdrawal from the landmark 2015 accord would undermine Trump's talks with North Korea by proving that America reneges on its promises. He said if Trump re-imposes sanctions, "basically killing the deal," Iran would no longer be bound by the pact's international obligations, freeing it up to resume enrichment far beyond the deal's strict limits.

"If the United States were to withdraw from the nuclear deal, the immediate consequence in all likelihood would be that Iran would reciprocate and withdraw," Zarif said. "There won't be any deal for Iran to stay in," he added.

Iran has been working feverishly to frame Trump's expected withdrawal as a major blot on the United States, just as America's closest allies in Europe try to persuade the president not to rip it up. The existing nuclear deal with Iran needs to be preserved, EU and Russian officials said yesterday. All European actors in the 2015 accord want the United States to stay in the deal aimed at restricting Iran's development of nuclear weapons. Trump, though, calls the pact "insane" and "ridiculous," although he has declined to say whether he will withdraw the U.S. by the May 12 deadline he has set. Trump said key flaws in the agreement are the failure to address ballistic missiles and Iran's activities in Yemen and Syria. The EU says those are separate issues.

Iran has outright rejected any changes to the deal, arguing that it's unfair to impose more demands beyond what Tehran agreed to already. Trump's strategy relies on the assumption that if the U.S. and the Europeans unilaterally agree to new demands, Iran will back down and voluntarily comply in order to continue enjoying the benefits. Under the 2015 deal brokered by President Barack Obama and world powers, Iran agreed to nuclear restrictions in exchange for billions in sanctions relief. And even if a so-called "add-on deal" with the Europeans is achieved, there is no guarantee it will satisfy Trump. His closest aides have said they can't predict with certainty what conditions would be enough to keep him in the pact.