Mr. Trump said the episode would have been far more serious if the aircraft had been a piloted vehicle, and not a drone.
It made “a big, big difference” that an American pilot was not threatened, he told reporters.
Last year, Mr. Trump pulled the United States out of the 2015 nuclear pact with Iran, over the objections of China, Russia and American allies in Europe.
He has also imposed punishing economic sanctions on Iran, trying to cut off its already limited access to international trade, including oil sales.
On Monday, Iran said it would soon stop abiding by a central component of the nuclear deal, the limit on how much enriched uranium it is allowed to stockpile.
Both Washington and Tehran said the downing of the drone occurred at 4:05 a.m. Thursday in Iran, or 7:35 p.m. Wednesday in Washington.
“This was an unprovoked attack on a U.S. surveillance asset in international airspace.”. »