President Donald Trump on Monday posted on his social media site an ominous message calling for the immediate evacuation of the Iranian capital of Tehran while he’s in Canada attending the G7 summit.

Trump had said more than once during the day that Iran cannot have a nuclear weapon. He emphasized that again in his social media post, writing “IRAN CAN NOT HAVE A NUCLEAR WEAPON.”

He said Iran should have signed the "deal" he told them to sign to prevent what he said was “a shame, and waste of human life,” referring to Israel’s attack last week. Trump ended the post with, “Everyone should immediately evacuate Tehran!”

Defense Secretary Pete Hegseth said he is headed to the White House Situation Room to meet with Trump and his national security team.

It comes as the U.S. has repositioned warships and military aircraft in the region to respond if the conflict between Israel and Iran further escalates.

Hegseth didn’t provide details on what prompted the meeting but said on Fox News late Monday that the movements were to “ensure that our people are safe.”

Hegseth’s chief spokesman, Sean Parnell, tweeted that “American Forces are maintaining their defensive posture.” The U.S. has helped Israel shoot down Iranian missiles.