By Michael Hernandez

WASHINGTON

President Donald Trump warned Iran Tuesday it should not attempt to re-start its nuclear program, as he threatened to potentially torpedo the nuclear agreement between Tehran and world powers.

"If they restart their nuclear program, they will have bigger problems than they ever had before," Trump said while welcoming French President Emmanuel Macron to the White House for the first official state visit of his presidency.

The nuclear deal was a centerpiece of discussions between the allies. Macron heavily favors maintaining the agreement, which saw Iran agree to widespread curbs on its nuclear program in exchange for billions of dollars in sanctions relief.

But Trump has repeatedly called the pact one of the worst negotiated agreements he has ever seen, and has threatened to pull the U.S. out of it unless Washington and its European allies strike a side deal with conditions largely unrelated to the original agreement spanning Iran's regional activities and its ballistic missile program.

Still, Trump appeared to leave room for keeping the U.S. in the deal during brief remarks before an expanded bilateral sit-down with Macron and French officials.

“It’s insane. It’s ridiculous. It should never have been made. But we will be talking about it,” he said.

His French counterpart, however, struck a markedly different tone, saying the agreement must be viewed in the wider context of Iran's regional behavior.

"We have a common objective, we want to make sure there’s no escalation and no nuclear proliferation in the region. We now need to find the right path forward,” Macron said in remarks translated from French.

Later during a joint press conference, Macron said Tuesday's discussions with his U.S. counterpart "make it possible to pave the way for a new agreement."

"And beyond our European partners we would like to involve the regional powers, and of course Russia and Turkey," Macron said. 

May 12 deadline

He and all of the U.S.' negotiating partners -- Germany, the European Union, the United Kingdom, China and Russia -- view the deal as the best way to prevent Iran from acquiring nuclear weapons. Iran has adamantly denied its program was intended to develop nuclear arms.

Trump has until a May 12 deadline to determine if he will continue to extend sanctions relief on Iran with or without the side deal he has sought from his Western allies. Should he fail to extend relief, the deal would almost certainly collapse.

"No matter the decision that President Trump will take, I would like us to work on a new deal with four pillars including what is already covered by the JCPOA," Macron said, referring to the formal title of the Iran deal: the Joint Comprehensive Plan of Action.

Trump further appeared to link the return of U.S. troops from the region to mitigating Iran’s potential to increase its regional influence, unlike previous statements where he stressed the importance of defeating Daesh.

"We’ll be coming home, but we want to leave a strong and lasting footprint," Trump said. "When they made the Iran deal what they should have done was included Syria."