Japanese police cleared cars left by protesters to block the roads to an American military base on the island of Okinawa on Sunday, in protest at the basing of 12 Bell-Boeing MV-22 tiltrotor aircraft there on Monday, Kyodo news reported.

Local people blocked all three roads to the Futenma base, and ignored police appeals to take them away, forcing the police to use heavy equipment to move them. There were no reports of arrests.

Earlier this month, the governments of Japan and the U.S. agreed to a plan for the basing of the tiltrotors in Japan, after a study by the Japanese concluded the aircraft did not pose special risks to local people. MV-22 flights will be limited to a minimum ceiling of 500 feet (150 meters) and they will not be allowed over populated areas.

Up to 24 MV-22s will be based at Futenma by 2014.

The V-22 Osprey family has had a troubled history, with several fatal crashes during its development. An MV-22 crashed during the African Lion military exercise in Morocco in April this year, prompting the Japanese to ask the U.S. for guarantees about the safety of the deployment in Okinawa.