Updated

A Japanese military helicopter carrying four crewmembers lost radar contact Tuesday while on a nighttime search and rescue flight training mission in central Japan and is feared to have crashed.

The UH-60J disappeared from radar while flying over the Pacific Ocean about 30 kilometers (18 miles) south of Hamamatsu, a coastal city in central Japan, soon after taking off from a nearby base, officials said.

Defense Minister Itsunori Onodera said rescuers spotted objects that appeared to be parts of the helicopter floating in the water, suggesting a crash.

The objects included what appeared to be a cabin door with the inscription "Air Self-Defense Force," a tail rotor, a fuel tank, a pair of wheels and a stretcher, the ministry said in a statement. Four military vessels and a coast guard ship were searching for the missing crewmembers late Tuesday.

Hamamatsu is about 250 kilometers (150 miles) southwest of Tokyo.

The helicopter's disappearance from radar is the latest in a series of incidents involving military aircraft this year. In May, four crewmembers were killed when an LR2 surveillance aircraft crashed on Japan's northern main island of Hokkaido. In August, another military helicopter, a SH-60J, crashed off the northern Japanese coast, leaving three of its four crew members missing.