WASHINGTON (AP) – Top administration officials and lawmakers are arriving at the White House for a briefing about Iran’s downing of an American surveillance drone in the Middle East amid mounting tension between the U.S. and Iran.

The White House invited House and Senate leaders of both parties and Democrats and Republicans on the House and Senate intelligence and Armed Services committees to meet with President Donald Trump on Thursday.

It’s unclear if Trump is planning a U.S. response. He told reporters that Iran made a “very big mistake” but also said he has the feeling that it might have been the result of someone being “loose” or doing something “stupid.”

Acting Defense Secretary Patrick Shanahan and Army Secretary Mark Esper, who Trump has said he’ll nominate as defense secretary, also arrived for the meeting.