While participating in a bilateral meeting with Canadian Prime Minister Justin Trudeau at the White House, Trump said he believes shooting down the drone was a "very foolish move," but added he believes the move may have been unintentional.
"I have a feeling that it was a mistake made by somebody that shouldn't have been doing what they did," said Trump. "And I'm not just talking the country made a mistake. I think that somebody under the command of that country made a big mistake."
He added that it "would have made a big difference" if the drone was manned and that the public will soon learn how the United States will respond.
"Obviously, you know we're not going to be talking too much about it, you're going to find out," Trump said.
In a statement, the Islamic Revolutionary Guards Corps said the Iranian air force downed the U.S.-made surveillance drone after it penetrated airspace near the Kouh-e Mobarak region in Hormozgan province, Iran's state-run Press TV reported.
The United States Central Command, however, answered Thursday the drone was shot down in international airspace.
"We did not have any aircraft in Iranian airspace today," said CENTCOM spokesman Capt. William Urban.
U.S. officials also said the drone was a MQ-4C Triton, not a Global Hawk as identified by Iran.
Iran's Revolutionary Guard said the drone broke "all aerospace rules and hiding its identification, which is against all aviation rules."
"We have no intention of war, but we are standing strong," IRGC Gen. Hossein Salami said on state TV.
The drone launched just after midnight on Wednesday and flew for four hours before it was shot down.
Senate Armed Services Committee Ranking Member Jack Reed, D-R.!., said Trump called a meeting about the incident with Senate Republican Leader Mitch McConnell, R-Ky., Senate Democratic Leader Charles Schumer, D-N.Y., and House Republican Leader Kevin McCarthy, R-Calif., on Thursday afternoon, NBC News reported.
The shootdown came two days after acting U.S. Defense Secretary Patrick Shanahan approved U.S. Central Command's request to deploy an additional 1,000 troops to the Middle East to confront Iranian aggression.
"The United States does not seek conflict with Iran," the secretary said in a statement. The deployment is "to ensure that the safety and welfare of our military personnel working throughout the region and to protect our national interests."
Tensions between the United States and Iran have risen for months, and the conflict deepened last week following an attack on two tankers in the Gulf of Oman the United States blamed on Tehran. Tensions first began to escalate following the Trump administration pulling out of the 2015 nuclear deal, citing it was "defective at its core."