President Trump warned Tuesday that Iran will face "bigger problems" if it resumes its nuclear weapons program, and said the nuclear agreement with Tehran fails to sufficiently monitor the regime's activities outside of its borders.

"If they restart their nuclear program, they will have bigger problems than they ever had before," Trump told reporters, adding that the agreement "should never have been made."

He made his comments during a sit-down with French President Emmanuel Macron, who has sought to convince Trump to preserve the agreement while working with the United States' European partners to amend it.

"The Iran deal is an important issue but we have to take a far broader picture which is security in the overall region," Macron said to reporters in the Oval Office. "What we want to do is contain Iran and its presence in the region."

Trump interjected to offer a harsher take on the nuclear agreement, which was negotiated by the Obama administration and could be dismantled after May 12, if he chooses to walk away from it.

"It just seems no matter where you go, especially in the Middle East, Iran is behind it, wherever there's trouble — Yemen, Syria, no matter where you have it — Iran is behind it," he said. "We're not going to allow certain things to happen that are happening."

But the president said he is willing to work with Macron to strike a deal that would keep the U.S. in the nuclear deal, pending certain modifications to the agreement.

"We're looking forward to doing something but it has to be done and it has to be done strongly," Trump said, declining to provide further details. "We're fairly close to understanding each other. Our one-on-one went very well."

Trump also dismissed suggestions that Iran could easily resume its nuclear program if the U.S. withdraws from the agreement.

"It won't be easy for them to restart it. They're not going to be restarting anything," he said.