Wreckage from a Japanese F-35A stealth fighter jet was found a day after it disappeared from the radar over the Pacific.
There was no word yet about the fate of the pilot on board, Defense Minister Takeshi Iwaya said on Wednesday.
"We believe that it crashed."
The fighter jet went missing around 7: 30 pm (1030 GMT) on Tuesday as it was flying a training mission about 135km east of Misawa, northeastern Japan, is a training mission.
The plane lost contact for about 30 minutes after taking off from Misawa Air Base with three other aircraft.
"I would like to apologize to the local residents for having caused them to concern," Iwaya said.
Japan is deploying the F-35As, each of which costs more than 1
According to defense ministry, the remaining 12 F-35A fighters have been grounded for the time being.