Photo/Illutration A U.S. military helicopter sits on a section of a dry riverbed along the Kinokawa river in Hashimoto, Wakayama Prefecture, on July 28. (Hiroshi Ohno)

HASHIMOTO, Wakayama Prefecture--Three U.S. military helicopters made an emergency landing here due to a mechanical problem before departing several hours later.

A resident reported to police and firefighters around 8:50 a.m. on July 28 that helicopters landed along the Kinokawa river.

Two large helicopters and a smaller one were found on a dry riverbed, which is located near the city government office, according to the municipal fire department.

A crew member told a firefighter that one aircraft experienced trouble but no one was injured, adding that the helicopters could take off in about 30 minutes.

The firefighter communicated with the crew member through an online translation program.

There was a report that a warning light was on inside an aircraft, according to the city government.

The helicopters left the site by around 11 a.m.

Police temporarily closed a road along the riverbed to traffic.

“We heard a loud helicopter noise and wondered what was going on,” a police official said. “We still don’t know what it was.”