Trump says 'no doubt' Iran drone was destroyed

President Donald Trump says there is "no doubt about it" that a US warship destroyed an Iranian drone, despite Iranian denials that it lost an unmanned aircraft.

Trump is speaking from the Oval Office Friday about the incident Thursday in the Strait of Hormuz.

His comments come a day after announcing that the USS Boxer took defensive action after an Iranian drone came within 1,000 yards (915 meters) of the warship and ignored multiple calls to stand down. "No doubt about it. We shot it down," he said.

Neither Trump nor the Pentagon spelled out how the Boxer destroyed the drone or provided any video or other evidence from the incident. Several US officials said the ship used electronic jamming to bring it down rather than hitting it with a missile. They spoke on condition of anonymity because they weren't authorised to speak on the record about the event.

Electronic jamming breaks the data links between a drone and its controller on the ground, causing it to crash. Such a move requires a vehicle-mounted, counter-drone device on the flight deck of the ship a device that's visible in official photographs of the Boxer released by the Pentagon after the incident.

National security adviser John Bolton said "there is no question this was an Iranian drone and USS Boxer took it out." An Iranian news agency reported Friday that the country's armed forces say all Iranian drones in the Persian Gulf returned safely to their bases.