Search efforts have been continuing since a Ground Self-Defense Force helicopter disappeared near Okinawa Prefecture's Miyakojima Island on Thursday with 10 people on board. Debris that appear to be pieces of the aircraft have been recovered.

Defense Minister Hamada Yasukazu said, "We are strengthening our readiness by significantly increasing the number of ground troops for the search from the initial 20 to more than 200."

Search crews have found lifeboats and window frames that may have been from the helicopter.

A Coast Guard patrol ship recovered a bent helicopter door and a broken rotor blade in waters north of Irabujima Island.

An official of the Miyakojima Coast Guard said, "So far, we haven't been able to find any clues as to where the 10 people could be, despite mobilizing four vessels. We're working closely with the Self-Defense Forces to find the missing as soon as possible."

The helicopter took off at 3:46 p.m. on Thursday. It disappeared from radar about 10 minutes later.

It may have been communicating with air traffic controllers at an airport on Shimojijima Island two minutes before it vanished. When the helicopter was inspected in late March, no abnormalities were found.

The missing people include Sakamoto Yuichi, the head of the Japanese Ground Self-Defense Force's 8th Division in Kumamoto Prefecture.