TOKYO -- A U.S. military HH60 Pave Hawk helicopter carrying four personnel crashed during a training exercise on Japan's southern island of Okinawa on Monday, officials said.
Three of the four crew members involved in the crash were in stable condition, the U.S. Air Force said in a statement. The remaining crew member had not been accounted for.
There were no casualties among local residents, a Japanese official told Reuters.
Video footage showed smoke rising from a fire on a remote mountainside.
The crash took place at 4 p.m. local time Monday (3 a.m. ET Sunday) at a maneuvering ground inside the U.S. Marine's Camp Hansen in central Okinawa.
"This is really regrettable. We are asking the U.S. side for a speedy supply of information," Japan's Defense Minister Itsunori Onodera told reporters, according to Reuters. "We plan to strongly demand for investigation into the cause of the accident and measures to prevent a recurrence."
Video footage from Japanese broadcaster NHK showed smoke rising from a fire on a remote mountainside. NTV and NHK said local police were attending the scene of the crash but did not have any information.
Residents of Okinawa, host to the bulk of U.S. military forces in Japan, have long complained at the scale of the U.S. military presence in the area, Reuters said.
NBC News' Alastair Jamieson and Reuters contributed to this report.