Wreckage from a Japenese F-35 stealth fighter jet has been recovered in the Pacific Ocean, according to Japan's Air Self-Defence Force.
The F-35A disappeared from radar while flying off the eastern coast of Aomori with parts of the jet being found late on Tuesday.
The pilot is still missing.
The jet went missing about 30 minutes after taking off from the Misawa Air Base along with three other F-35As for anti-fighter battle training.
Defence Minister Takeshi Iwaya told reporters the cause of the disappearance was not immediately known, adding the 12 other F-35s at the Misawa Air Base would be grounded.
"We collected parts from the jet's tail fins in the area, so we think it had crashed," said Mr Iwaya.
"The missing pilot signalled the need to abort the mission and shortly after that communication and radar contact was lost."
The missing pilot is a man in his 40s, Mr Iwaya said.
The US says a Navy P-8A maritime patrol aircraft and guided-missile destroyer USS Stethem are assisting the Japanese with their search and rescue efforts for the pilot.
The aircraft is based at Misawa Air Base on rotational deployments, while USS Stethem is forward-deployed to Yokosuka in Japan.
The P-8A aircraft was involved in the search overnight.
Japan started deploying the expensive US-made F-35s last year as part of its plan to bolster its defence spending and weapons capability to counter potential threats from North Korea and China.
Under guidelines approved in December, Prime Minister Shinzo Abe's government plans to buy 147 F-35s, including 105 F-35As, costing about 10 billion yen (£69 million) each.
Last year, a US F-35B crashed near an air base in South Carolina which was said to be the first since the aircraft became operational in 2006.
The UK is also part of the F-35 programme and the Ministry of Defence (MOD) currently owns 17 of the F-35B variant, with a total of 138 expected to be bought.
An MOD spokesperson said: "We are sad to hear of the ongoing issue in Japan concerning one of their F-35 A Aircraft.
"There is currently very little information concerning the incident.
"We are in close contact with the US Joint Programme Office who will provide updates as soon as information becomes available.
"Safety is of the utmost importance and very closely managed on the F-35 programme.
"We will continue to review the situation as further information becomes available."