U.S. Marine Corps and Ground Self-Defense Force personnel began a joint exercise Tuesday in Shiga Prefecture.

During the exercise, which will last through Oct. 18 in the Aibano Training Area, U.S. Marine Corps MV-22 Osprey aircraft will be used for the first time in a joint military drill in Japan.

The tilt-rotor Ospreys, based at U.S. Marine Corps Air Station Futenma in Okinawa, have been the target of local opposition.

One or two Ospreys are expected to join the exercise on Oct. 16, according to the Defense Ministry. Shiga Prefecture has demanded that the aircraft not fly over populated areas or above Lake Biwa.

The two forces were scheduled to deploy a combined contingent of 330 troops, but this number has been reduced to 230 because a powerful typhoon has led to a delay in the arrival of some U.S. elements.

A separate U.S.-Japan military exercise is scheduled for Oct. 25 in Kochi Prefecture, based on the scenario of a massive earthquake and tsunami centered on the Nankai Trough, which stretches between the Izu Peninsula in Shizuoka Prefecture and the ocean floor off Kyushu.

In the exercise, two Ospreys will be mobilized for search and rescue operations at sea as well as for the transport of Self-Defense Forces elements and relief goods to affected areas.