Laser-like rays were beamed at U.S. military aircraft flying near the Futenma base in Okinawa five times since July 2014, an official with the U.S. Marine Corps said.

The official said Monday that such flight-interfering activities "pose a threat to the safe operation" of aircraft at U.S. Marine Corps Air Station Futenma.

While there have been no reports of injuries in relation to the beams, such strong lights could disable a pilot's vision and lead to a crash, especially when pilots are using a night vision device.

A total of 48 U.S. military aircraft, including 24 MV-22 Ospreys, are stationed at Futenma, which is located in a crowded area in the city of Ginowan.

After the U.S. Marines reported the incidents, the Okinawa Prefectural Police started an investigation on suspicion of forcible obstruction of business.

The transport ministry said there have been at least 150 cases of lasers beamed at aircraft flying in Japan since July 2010.