A US military helicopter crashed off the coast of the southern island of Okinawa, Japanese officials say.

According to the Kyodo state news, police confirmed that the helicopter crashed as it tried to land on a ship at sea. However, the exact cause of the crash is not yet known.

Kyodo said, 17 crew members were rescued, and seven people were injured.

A Japanese defense ministry official said there were five people on board three among them were rescued while two were missing.

“We received a report that the aircraft fell in waters east of Okinawa’s main island, we have dispatched patrol boats and planes to the site at the request of the US military,” a coastguard official said.

Okinawa is home to more than half of the 47,000 US service personnel stationed in Japan as part of a defense alliance.