U.S. Vice President Joe Biden will visit Japan and China this week as a dispute seethes over Beijing's recent claim of a large swath of airspace in the region.
The Chinese declaration less than two weeks ago has prompted a war of words between governments and flights through the contested air zone by military planes from the United States, China, Japan and South Korea.
"Biden's trip was supposed to be about trade and the economy. now in fact it's all about the Chinese military," reports CNN's Barbara Starr.
The uneasy situation in the sky over the East China Sea has raised fears that a midair incident could cause circumstances to spiral out of control. It has also fueled concern about how far China is willing to go to pursue its interests in the Asia-Pacific region and push back against U.S. influence.
U.S. officials say that during his visit this week, Biden will raise American concerns about Beijing's newly declared air defense identification zone - which the United States and Japan reject - and encourage dialogue among countries in the region to ease tensions.
He will also "make the broader point that there is an emerging pattern of behavior by China that is unsettling to China's own neighbors," a senior Obama administration official said in a briefing last week.
U.S. State Department spokeswoman Jennifer Psaki reiterated Monday that Washington doesn't recognize the air defense zone nor China's demand to be notified of plans by jets from other nations to fly into the area. Psaki said the U.S. position is separate from any U.S.-based airlines' decisions to comply with China's demands.
"The U.S. Insists it will continue flying military aircraft through the Chinese zone and has begun a long-plan deployment of advance P-8 reconnaissance aircraft to japan that can carry torpedoes, missiles, bombs and mines," Starr says.
"Now the U.S. Is already calling on china not to establish yet another restriction zone and Biden arrives in Beijing on Wednesday to talk to Chinese leaders about all of this."