Near the northeastern Okinawa Island fishing port of Nago, some 50 men and women in their 60s through their 90s have been staging a daytime sit-in at a makeshift camp for more than 200 days.

They hope to block the central government from constructing an offshore joint U.S. military-civil airport -- a facility agreed upon by both nations about a decade ago.

The planned airport off Nago's Henoko coastal district is expected to take over the helicopter operations of the U.S. Marine Corps Futenma Air Station in Ginowan. The replacement site is part of a 1996 agreement between Japan and the United States to return the Futenma land to Japan after an alternative facility is built in Okinawa.