OSAKA — With Sunday's win in Nago, Okinawa, by a mayoral candidate who is opposed to relocating the Futenma air base to the city's Henoko district, calls to revise the 2006 accord and relocate the facility outside the prefecture are growing, placing Tokyo and Washington under increased pressure to pick another site.

With the U.S. insisting on adherence to the 2006 agreement, and with officials, policy experts and some media in Tokyo and Washington warning that the issue is damaging the bilateral relationship, Prime Minister Yukio Hatoyama is now under intense pressure to decide a site before his self-imposed May deadline.

Susumu Inamine, 64, a former chairman of Nago's board of education, won a closely fought contest with incumbent Yoshikazu Shimabukuro, 63, who had earlier voiced his willingness to accept the terms of the 2006 accord.