Japan's Abe suffers setback with Okinawa election loss

TOKYO (Reuters) - A city mayor opposed to a plan to relocate a controversial U.S. airbase on Japan's Okinawa island was re-elected on Sunday, creating a political headache for Prime Minister Shinzo Abe and threatening friction with Washington.

Delays in relocating the U.S. Marines' Futenma air base, a move first agreed between Tokyo and Washington in 1996, have long been an irritant in U.S.-Japan ties. Abe is keen to make progress on the project as he seeks tighter ties with the United States in the face of an assertive China.