TOKYO/WASHINGTON - US Vice President Joe Biden will seek a delicate balance between calming military tensions with China and backing ally Japan against Beijing on a trip to Asia this week that is being overshadowed by a territorial row in the East China Sea.
Japan reiterated on Monday that Tokyo and Washington had both rejected Beijing's move to set up an air defence zone that includes islands at the heart of a bitter Sino-Japanese feud - despite the fact that three US airlines, acting on government advice, are notifying China of plans to transit the zone.
Washington said over the weekend this did not mean US acceptance of the zone, and last week sent two B-52 bombers into the area without informing China.
"The US government has made it clear that it is deeply concerned about China's establishment of the air defence identification zone, and that it will not accept China's demands regarding operations in the zone," Japanese Chief Cabinet Secretary Yoshihide Suga told a news conference.
Japan's two biggest airlines are following a request from their government not to submit flight plans in advance, which China has demanded from all aircraft since it announced the creation of the zone last month.
South Korean authorities have also advised the country's airlines not to submit flight plans to China for flying through the zone, which overlaps with a submerged rock claimed by Beijing and Seoul.
Chinese Foreign Ministry spokesman Hong Lei said China appreciated the United States urging its airlines to notify China of flight plans, but chastised Japan for "deliberately politicizing" the issue.
Sino-Japanese ties, often fraught due to regional rivalry, mutual mistrust and bitter Chinese memories of Japan's wartime occupation, have become increasingly acrimonious because of a quarrel over tiny islands claimed by both Tokyo and Beijing.
In Tokyo on Tuesday, Biden will likely assure Japan that a military alliance with the United States dating back to the 1950s remains valid as the government of Prime Minister Shinzo Abe wrangles with China over the islands.