Many in Tokyo and Washington will be keeping a close eye on a mayoral election Sunday in Okinawa that is likely to affect a matter of long-standing concern between the two governments.

In the Nago mayoral race, incumbent Tateo Kishimoto, 58, is being challenged by 42-year-old Yasuhiro Miyagi, a former Nago assemblyman who opposes the planned construction of a joint civilian-U.S. military airport off the city's coast.

"All our efforts over the years (regarding the proposal) would come to nothing should Mr. Kishimoto lose," an official at the Defense Facilities Administration Agency in Tokyo said.