A Ground Self-Defense Force helicopter crashed Sunday while performing a low-altitude flight demonstration for the public in Sasebo, Nagasaki Prefecture, but the two personnel on board were unharmed, police said.

None of some 2,000 people who gathered in the Ainoura garrison for events commemorating the base's 50th anniversary was injured in the 11:30 a.m. accident, the police said. The AH-1S Cobra attack helicopter came down about 150 meters from the crowd.

The accident occurred when the Cobra's main rotor scraped the ground while it was trying to make a right turn flying at low altitude. The two crew on board -- a 53-year-old major and a 32-year-old first lieutenant -- managed to escape unassisted.

The helicopter was one of three flying over the base for the event, which included mock fighting involving tanks and other weapons.

After the accident, base officials decided to cancel a planned artillery exhibition but went on with other attractions such as allowing visitors to ride on GSDF vehicles.