TOKYO (AFP) - Six people were injured when a US military helicopter failed to land properly on an American ship during an exercise off Japan's Okinawa island on Wednesday, the US military said.

A US Army H-60 helicopter was "damaged during a hard deck landing" aboard the vehicle cargo ship USNS Red Cloud 32km east of the island, US Forces Japan said in a statement.

"The helicopter was conducting a local training mission," the brief statement said, adding that the cause of the accident is under investigation.
While further details were not available, Japanese local media said a total of 17 crew members were on board when the accident occurred.

Japan's coastguard and public broadcaster NHK earlier said seven crew members were injured.

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

Japan said last week it would temporarily halt work on a controversial new US military base in southern Okinawa as talks continue with local officials opposed to the project.