OSAKA (Kyodo) A Ground Self-Defense Force helicopter crashed Sunday at the GSDF's Yao garrison in Yao, Osaka Prefecture, seriously injuring one of the four crew members, police said.

The other three were also hurt, but the injuries are not life-threatening, the GSDF said. The four — two pilots and two mechanics — were taken to a nearby hospital, a local fire station said.

The UH-1 helicopter belonged to the Middle Army Aviation Group. It was taking a test flight after a regular maintenance check and was hovering when it crashed, the GSDF said.

According to the police, there were no immediate reports of civilians being injured by the crash.

The GSDF is investigating the cause of the accident.