Mr. Trump predicted that Israel would not slow its assault on Iran, which has largely decapitated the Islamic republic's military command and inflicted significant damage to its controversial nuclear program.
"You're going to find out over the next two days. You're going to find out. Nobody's slowed up so far," he said, hours after issuing an ominous warning that all of Tehran's roughly 10 million inhabitants should "immediately evacuate."
Asked about that warning on Air Force One early Tuesday, Mr. Trump said he wanted "people to be safe," without offering any further explanation. Israel on Monday warned about 300,000 residents in a central district of Tehran to evacuate, pending attacks in the area.
Mr. Trump suggested the reason he didn't want to stay in Canada was because he couldn't confidentially monitor developments in the Middle East. He said he could be "more well versed" in the White House Situation Room and avoid cellphones. "I don't believe in telephones — because people like you listen to them," he told reporters on the plane. "Being on the scene is much better."
A source with knowledge of the talks told CBS News on Monday that Tehran had indicated to negotiators in Qatar and Oman that it was prepared to discuss a new deal with the U.S. on its nuclear program, but not while it was still under Israeli attack.
The president said it was possible he could send special envoy Steve Witkoff or Vice President JD Vance, or both, to meet with Iranian negotiators, but "it depends what happens when I get back" to Washington.
"I don't know," Mr. Trump added. "I'm not too much in the mood to negotiate."
Addressing any possible threat to U.S. interests in the region, Mr. Trump said Iran knew not to target U.S. forces, as the U.S. would "come down so hard if they do anything to our people."
The president declined to say whether Joint Chiefs of Staff Chairman Lt. Gen. Dan Caine and Defense Secretary Pete Hegseth had provided him with options in the event Iran does attack U.S. bases in the Middle East.
"I can't tell you that," he said.
Asked if it would take U.S. involvement to destroy Iran's nuclear program, Mr. Trump said he hoped it would be "wiped out long before that."
Trump says Iran was "very close" to obtaining a nuclear weapon
Prime Minister Benjamin Netanyahu has framed the attack he ordered on Iran late last week as an "existential" battle for Israel's survival. He claimed intelligence — which Israel has not shared publicly — showed the country was "racing" toward the development of a nuclear weapon. Netanyahu, along with all recent U.S. presidents including Mr. Trump, have always said they could not allow Iran to obtain a nuclear weapon.
Just several months ago, however, Director of National Intelligence Tulsi Gabbard delivered an assessment to lawmakers that said U.S. agencies continued "to assess that Iran is not building a nuclear weapon and Supreme leader Khomeini has not authorized the nuclear weapons program that he suspended in 2003."
Gabbard said the U.S. was continuing to "monitor closely if Tehran decides to reauthorize its nuclear weapons program," and she noted that "in the past year, we've seen an erosion of a decades long taboo in Iran on discussing nuclear weapons in public likely emboldening nuclear weapons advocates within Iran's decision-making apparatus."
Asked on Air Force One about that assessment from Gabbard, that Iran was not building a nuclear weapon, Mr. Trump told reporters: "I don't care what she said. I think they were very close to having them."