WASHINGTON (Kyodo) The top U.S. diplomat for Asia renewed a call Thursday for Japan to stick to a 2006 bilateral deal and relocate the U.S. Futenma air base in Okinawa, as Washington sees it as the best possible option.

In written testimony before a Senate Foreign Relations Committee subcommittee, Kurt Campbell, assistant secretary of state for East Asia and Pacific affairs, said the U.S.-Japan alliance is a "cornerstone" of U.S. engagement in Asia.

"The May 2006 agreement on defense transformation and realignment will enhance deterrence while creating a more sustainable military presence in the region," he said.