WASHINGTON — President Donald Trump on Thursday said the public will "find out" about a U.S. response to Iran shooting down an American military drone in the Persian Gulf that the president insisted was in international territory.

Asked at the White House about a U.S. response, Trump said, “Obviously, you know we're not going to be talking too much about it," before adding, "You're going to find out."

"Iran made a very bad mistake," the president continued. "The drone was in international waters clearly. We have it documented."

Later Thursday afternoon, Trump hosted Senate Majority Leader Mitch McConnell, R-Ky., Senate Minority Leader Chuck Schumer, D-N.Y., House Speaker Nancy Pelosi, D-Calif., and House Minority Leader Kevin McCarthy, R-Calif., at the White House for a briefing on Iran, Senate Armed Services Committee Ranking Member Jack Reed, D-R.I., and multiple congressional sources told NBC News.

"The president may not intend to go to war here, but we're worried that he and the administration may bumble into a war," Schumer said back at the Capitol after attending the White House briefing. "We told the room that the Democratic position is that Congressional approval must be required before funding any conflict in Iran."

Schumer and other Democrats have urged Republican leadership to allow a vote next week on the National Defense Authorization Act, which would require congressional approval in order for funds to be used in a military action against Iran.

Trump's comments, made at the White House during an appearance with Canadian Prime Minister Justin Trudeau, came hours after Iran said it downed a drone and claimed it was in Iranian air space.

While Trump said the Iranian action was "a new fly in the ointment" and a "very foolish move," he also said it might have been a "mistake."

"I have a feeling that someone under the command of that country made a big mistake," he said. "I find it hard to believe it was intentional. It could have been someone who was loose and stupid who did it."

Trump added that it would have made a "big difference" if there had been a person in the drone.

The president's earlier statement on Twitter that Iran had made a "big mistake" was the first official White House response to the downing of the drone, which occurred around 4 a.m. Thursday morning in Iran (just after 7:30 pm ET Wednesday evening).

A meeting was held at the White House for Thursday morning to discuss the U.S. response. Outgoing acting Defense Secretary Patrick Shanahan and his replacement, Mark Esper, were among those expected to attend.

At roughly the same time, House and Senate leaders and key committee chairs planned to attend an Iran briefing to discuss their concerns and hear about the situation from officials, Pelosi told reporters early Thursday.

Later in the day, Pelosi planned to hold a briefing for the House Democratic caucus with Wendy Sherman, who helped negotiate the Iran nuclear agreement that Trump withdrew from, and former CIA Director John Brennan.

Pelosi said Thursday morning that "high-tension wires are up in the region" and cautioned against any "reckless" moves by the U.S.

"We have to be strong and strategic about how we protect our interests. We also cannot be reckless in what we do. I don't think the president wants to go to war. There's no appetite for going to war in our country," she said at her weekly news conference on Capitol Hill. "This is a dangerous neighborhood. A miscalculation on either side could provoke something that could be very bad in terms of security and our interests."

Although both nations have acknowledged that the U.S. military drone was downed, they disagreed on whether it had violated Iranian airspace: Iranian’s Revolutionary Guard said it did, but U.S. officials disputed that, saying it was in international airspace.