A US military helicopter Monday crashed in Okinawa, Japan's southernmost prefecture, a media report said.
The accident took place at about 4.30 p.m. Monday inside a US military camp in Ginoza village, reported Xinhua citing NHK.
The fate of those onboard the chopper was not known.
Okinawa government and residents have demanded for long to move US bases out of the prefecture, especially the key Futenma airbase, due to safety concern.
However, Japan's central government and the US, despite the opposition, continue to deploy more US aircrafts to the prefecture, which holds more than 70 percent of US bases in Japan.