In this Sunday, Dec. 2, 2012 photo, graffiti against the U.S. military base is painted on a wall where a gas station used to stand across from the U.S. Air Force Kadena air base in Kadena, Okinawa, southwestern Japan. Okinawans are angry that Japan approved the deployment of 12 Osprey aircraft, which began in October, though the government has asked for additional assurances of the aircraft's safety. Washington said the Osprey is safe and is needed to ensure regional security. (AP Photo/Junji Kurokawa)
TOKYO (AP) -- Japanese defense and police say a U.S. military helicopter has crashed at an American base on the southern island of Okinawa.
Defense Ministry officials said a helicopter crashed at Camp Hansen. Television footage showed smoke rising from a spot in the forest, although it was unclear whether the aircraft was on fire.
Three of the four crew members on board survived, Japan's NHK public TV quoted Defense Minister Itsunori Onodera as saying. Their conditions were not known.
Okinawa prefectural police said there were no reports of injuries or damage outside the base.
The crash comes amid Okinawan opposition to the Marine Corps' additional deployment of 12 MV-22 Osprey transport aircraft. About half of the 50,000 troops in Japan are based on Okinawa under a Japan-U.S. security pact.