A Japanese Global Hawk unmanned aerial vehicle went missing over the Sea of Japan on Tuesday, according to local media.
The Japan Air Self-Defense Force launched a search operation after losing communication with the drone, Kyodo News reported.
Communication was lost at around 12.58 pm (0358GMT) while the drone was flying about 50 kilometers (31 miles) off the coast of Tottori Prefecture in western Japan.
The defense force declined to elaborate on the nature of the aircraft's mission, explaining it as a training flight.
The Coast Guard later said debris believed to be from the Global Hawk was found at sea.
Japan has three active RQ-4 Global Hawk surveillance drones bought from US defense company Northrop Grumman.
They were first deployed at Misawa Air Base in Aomori Prefecture, northeastern Japan, in 2022.
