"That is why we must put an end to Iran's continued aggression and nuclear ambitions", Trump said.
After that, Congress will have 60 days to decide whether to renew sanctions against Iran.
Trump, who called the pact an "embarrassment" and "the worst deal ever negotiated", faces an October 15 deadline for certifying that Iran was complying with its terms.
Opposition to the deal was a major part of his campaign a year ago. Trump referred to the impromptu dinner and photo shoot as "the calm before the storm", before praising the military and reiterating his array of military options with respect to North Korea.
On Thursday, Donald Trump has discussed this issue with the military leaders and expressed his own vision of this aspect of foreign policy.
"You guys know what this represents?" he asked.
"Maybe it's the calm before the storm", the president replied.
"What's the storm?" a reporter asked. Trump grinned mischievously and waved his hand in a semi-circle as the military leaders flanked him.
Trump was also set to announce a series of measures to punish Iran for its regional behavior.
President Donald Trump said late Thursday that a meeting with his military leaders was "the calm before the storm", but what he meant by his ominous comment remained unclear.
Citing "people briefed" on the matter, the Washington Post reports Trump is expected to deliver a speech, possibly on October 12, laying out his administration's new Iranian policy. "ISIS? North Korea? Iran?".
According to the Washington Post, the White House had informed the press that the president would not be making any further appearances that evening.
Defense Secretary James Mattis told lawmakers Tuesday it is in the best intertest of US national security to remain in the deal.
Iran has warned that the deal is not renegotiable - but added that if the other worldwide signatories remain on board it could be salvaged.
He responded: "You'll find out".
"I believe at this point in time, absent indications to the contrary, it is something that the president should consider staying with", Mattis added.
He added that the USA must "do what we must do to prevent that from happening and it will be done, if necessary".