US military aircraft crashes in sea off Japan killing at least one

Japan's coast guard said what appeared to be wreckage from the tilt-rotor V-22 Osprey and one "non-responsive" person had been found some 3 km from Yakushima island.

Fishing boats in the area found three people in the surrounding waters, a representative of a local fisheries cooperative said, adding their condition was unknown.

Another Osprey landed safelyat the island's airport on Wednesday afternoon around the time of the crash, a spokesperson for the local government said.

U.S. forces in the region were still gathering information, a spokesperson said.

The United States, which pledged to defend Japan after its defeat in World War II, has about 54,000 U.S. troops in the country, many in the strategically important southern island chain, amid growing Chinese military assertiveness in the South China Sea.

The crash happened just before 3 p.m. (0600 GMT) with witnesses saying the aircraft's left engine appeared to be on fire as it descended, media reported.

Japan, which also operates Osprey aircraft, said on Wednesday it had no plans to ground the aircraft but had asked the U.S. military to investigate the crash.

Developed jointly by Boeing BA.N and Bell Helicopter, the Osprey can fly both like a helicopter and fixed-wing aircraft and is operated by the U.S. Marines, U.S. Navy and the Japan Self Defense Forces.

The deployment of the Osprey in Japan has been controversial, with critics saying it is prone to accidents. The U.S. military and Japan say it is safe.

In August, a U.S. Osprey crashed off the coast of northern Australia while transporting troops during a routine military exercise, killing three U.S. Marines.

Another crash-landed in the ocean off Japan's southern island of Okinawa in December 2016, prompting a temporary U.S. military grounding of the aircraft.

(Reporting by Kiyoshi Takenaka, Tim Kelly and Satoshi Sugiyama; Writing by John Geddie; Editing by David Dolan, Gerry Doyle and Nick Macfie)