A Japanese court ruled Friday that Okinawa Gov. Takeshi Onaga's revocation of a reclamation permit for a U.S. military base on the southern island was illegal, supporting the central government plan to go ahead with the reclamation despite protests by local residents.
The decision is the latest development in a legal battle between Okinawa and Tokyo over the relocation plan that has stalled for 20 years.
Okinawa said it will appeal the Fukuoka High Court ruling to the Supreme Court.
Onaga revoked approval for the permit last October. The reclamation is needed so the U.S. can relocate Marine Corps Air Station Futenma to a less populated area on the island. The work involves filling in part of a bay to create off-coast runways for the air station, which is now in a crowded neighborhood.
The relocation is based on a 1996 bilateral agreement to reduce the burden of the U.S. military presence on Okinawa.
Opponents say relocation doesn't really reduce their burden, and want the base moved off Okinawa entirely, but a prospect for a compromise is still unclear.
Okinawa, under the Japan-U.S. security treaty, hosts half of 50,000 U.S. troops based in Japan. Many residents on the island complain about the large American troop presence, as well as noise, pollution and crime from the bases.