TOKYO, Nov 30 (AFP) - Rescuers scoured waters off Japan on Thursday (Nov 30) as they searched for seven missing US Air Force personnel whose Osprey crashed during a training exercise, in the latest incident involving the tilt-rotor military aircraft.

One unconscious person was found in the sea on Wednesday and later declared dead after the aircraft crashed off the island of Yakushima, according to the Japanese coastguard.

The US Air Force Special Operations Command said eight crew had been aboard the CV-22B Osprey as it performed "a routine training mission" out of Yokota Air Base in Japan.

"The cause of the mishap is currently unknown," it said in a statement Wednesday, with emergency personnel "on scene conducting search and rescue operations."

An emergency management official in the Kagoshima region where the crash took place said police had received information that the aircraft had been "spewing fire from a left engine".

Photos released by the coastguard showed what appeared to be an overturned yellow life raft and other debris in the water off Yakushima, which lies south of Japan's southernmost main island of Kyushu.

A Japanese coastguard spokesman told AFP on Thursday that the search operation had been continuing through the night and that "aircraft and ships are being deployed".

A coastguard statement had earlier placed the number of crew on board at six.

Photo from AFP