President Trump met with top members of the House and Senate at the White House Thursday, after Iran shot down a U.S. drone flying over what the U.S. says was international airspace over the Strait of Hormuz. Iran claims the drone was in its airspace.

The meeting, which included House Speaker Nancy Pelosi, Senate Minority Leader Chuck Schumer, Senate Majority Leader Mitch McConnell and other top Republicans, Secretary of State Mike Pompeo, Defense Secretary Mark Esper, and national security adviser John Bolton, came after Mr. Trump told reporters Iran's downing of the drone may have been a mistake.

A source in the meeting tells CBS News "Face the Nation" moderator Margaret Brennan the meeting was a positive one, without arguments. Mr. Trump, the source said, went around the room and gathered input, although he did not run through options. No one objected to the premise of a U.S. response, but that had many possible permutations, according to the source.

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"We had a good briefing," McConnell told reporters back on Capitol Hill. "I think you know who was there, and I can confirm what was probably already written, which was that the UAV was fired on from Iranian soil and it was international waters, and beyond that I think the administration is engaged in I think what I would call 'measured responses.'"

After the meeting, Pelosi issued a statement emphasizing the importance of engaging with allies. The U.S. has largely stood alone in its increasing criticisms of Iran amid escalating tensions.

"In light of the targeting of an unmanned U.S. drone by Iran, it is essential that we remain fully engaged with our allies, recognize that we are not dealing with a responsible adversary and do everything in our power to de-escalate," Pelosi said. "This is a dangerous, high-tension situation that requires a strong, smart and strategic, not reckless, approach."

Earlier in the day, Mr. Trump appeared to break with his own Pentagon when, in an Oval Office meeting with Canadian Prime Minister Justin Trudeau, he said that the incident might have been the fault of someone "loose and stupid."

"I find it hard to believe it was intentional," Mr. Trump said, adding that it was perhaps a general or someone "under command" of the Iranian government who mistakenly authorized the strike.

It's unclear what the U.S. response to Iran will be. Publicly, Mr. Trump took a wait-and-see approach Thursday, when he was asked whether the U.S. would respond with a strike of its own. "You'll soon find out," he responded.