US military personnel have received what could be parts of the wreckage of a US Osprey military aircraft, which had been stored in a warehouse in Yakushima Town in southwestern Japan after they were retrieved by local fishers.

Japan's Coast Guard and Self-Defense Forces continued search and rescue efforts on Sunday, four days after the aircraft crashed into the sea off Yakushima Island in Kagoshima Prefecture.

One of the eight personnel who were on board when the Osprey went down on Wednesday has been confirmed dead, while seven others remain unaccounted for.

The US Air Force also said the nuclear-powered aircraft carrier USS Carl Vinson is taking part in the search for the missing crewmembers.

On Sunday morning, US military personnel visited the warehouse and loaded the stored items onto a truck. The wrapped items were loaded on a US transport aircraft at Yakushima Airport.

Two US Ospreys were seen flying over the waters off Yakushima Island on Sunday.

The regional bureau of Japan's Defense Ministry said those Ospreys belong to US Marine Corps Futenma Air Station and have been carrying out search operation since Saturday.

Kagoshima Governor Shiota Koichi urged the US through the regional bureau of the Japan's Defense Ministry to assure safety and not expose residents to risks.