Japan's Self-Defense Forces have dispatched a submarine rescue ship to join efforts to find a helicopter that went missing off the southern prefecture of Okinawa on Thursday.

Ten people were on board the chopper, including the head of the Ground Self-Defense Force's 8th Division. It disappeared while flying over waters off Miyako Island. All those aboard are still unaccounted for.

The rescue ship is equipped with a remotely operated unmanned vehicle. If sonar detects something like a helicopter, the vehicle would be used to confirm the finding. Divers could also be sent in to search.

The chopper is equipped with an emergency location transmitter. The device is designed to automatically activate upon impact or water immersion. But the GSDF says it has not confirmed any distress signal so far.

The GSDF on Saturday received a report of what appeared to be a person floating near the coast of the nearby island of Irabu. But the follow-up search found nothing.

The SDF and the Coast Guard continue their search for the missing helicopter and personnel.