Japan and the United States have narrowed their options down to two on the relocation of the U.S. Marine Corps Futenma Air Station in Okinawa, but disagree on which one, a Pentagon official said Thursday.

The official confirmed the U.S. Defense Department is pushing to have an airport built just off the coast of the Marines Corps Camp Schwab in the Henoko district of Nago. The Defense Agency wants to construct the airport within camp limits.

Originally, it was decided a joint civil-military airport with a 2,500-meter-long runway would be built off Henoko at another site beyond the reef, but work never started due to local opposition.

The two sides have now basically agreed to build a military airstrip, with a 1,500-meter-long runway to accommodate the helicopter operations now at the Futenma base in Ginowan.