TOKYO » Six Osprey hybrid aircraft were transferred to a U.S. base on the southern Japanese island of Okinawa today — and were greeted by hundreds of protesters outside the fence showing their concern about the plane’s safety.

The aircraft — which takes off like a helicopter and flies like an airplane — flew safely from Iwakuni, on the Japanese main island, to U.S. Marine Corps Air Station Futenma, according to Capt. Justin Jacobs with the Third Marine Expeditionary Force in Okinawa.

All told, 12 of the MV-22 Osprey aircraft will be stationed at Futenma, which is surrounded by residential areas. It isn’t clear when the remaining six will be moved.

Many Okinawa residents oppose their deployment after crashes in Morocco and Florida earlier this year, saying they are not safe to fly in Okinawa’s crowded environment. An incident in North Carolina last month that officials called a “precautionary landing” further aggravated the sentiment.

Japan’s central government gave the green light for operations to begin after a visit last month by U.S. Defense Secretary Leon Panetta, who said Washington is confident in the safety of the aircraft.

Photographs and TV footage today showed hundreds of protesters gathered near Futenma chanting and holding up banners opposing the Osprey.

“Who can say, “We understand” about something like this that could fall on our heads? It’s extremely disappointing and regrettable,” Okinawa Gov. Hirokazu Nakaima told reporters.

The Osprey deployment plan has reignited longstanding anger over the heavy presence of American troops on Okinawa and has become a headache for officials in Tokyo and Washington hoping to calm anti-base sentiment. More than half of the roughly 50,000 U.S. troops stationed throughout Japan are based on Okinawa.

Futenma also arouses local frustration because the two countries decided to close it more than a decade ago, but it has remained in operation because a replacement site hasn’t been readied.