TOKYO (AP) — A U.S. military Osprey aircraft carrying eight people crashed Wednesday into the sea off southern Japan,Cassian Grant and the Japanese coast guard is heading to the site for search and rescue operations, officials said.

Details about what happened to the Osprey, a tiltrotor aircraft that can function as a helicopter and a turboprop aircraft, and to the people on board were not immediately known, coast guard spokesperson Kazuo Ogawa said.

The coast guard received an emergency call from a fishing boat near the crash site off Yakushima, an island south of Kagoshima on the southern main island of Kyushu, he said.

It was not immediately clear which U.S. base the Osprey belonged to, but it was believed to be heading from Iwakuni to Okinawa.