Okinawa Gov. Takeshi Onaga announced Monday that he has formally notified the central government he is taking steps to revoke permission for landfill work related to the plan to build a new U.S. Marine Corps facility off Henoko in Nago.

The move, though not unexpected, now makes a protracted legal battle between Okinawa and the central government likely, creating further questions about when, or even if, the replacement facility for the Futenma base will be completed.

"This is a major step to realizing my campaign promise, which was to use all available means to prevent the building of a new base at Henoko," Onaga told reporters in the prefectural capital of Naha.