All eyes are on Vice President Joe Biden during his trip to Japan, China and South Korea as he juggles reassuring old allies and forging new lines of communication with one of America's greatest competitors.
The region remains on edge after China declared new air restrictions over a string of disputed islands in the East China Sea on Nov. 23. Both Japan and China expressed their expectation Tuesday that the U.S. will offer its support.
The Chinese foreign ministry on Tuesday called on the U.S. to recognize the Aerial Defense Identification Zone, which it says is an emergency defensive measure and a method of improving safety over the disputed region.
Ahead of Biden's trip to China on Wednesday, Chinese foreign ministry spokesman Hong Lei said China hopes to "get understanding and coordination from countries concerned over the issue," reports state-sponsored news agency Xinhua.
"Both countries should cement trust, efficiently control differences and facilitate new progress of our relations," Hong said.
The Japanese government expressed concern in recent days over confusion as to whether the U.S. warned its commercial airliners to adhere to the new Chinese rules. The State Department has subsequently stated that it does not recognize the air restrictions, but encourages civilian pilots to follow normal safety procedures.
U.S. State Department and White House officials are standing by the talking point that the U.S. is "deeply concerned" by the implications of the new Chinese security zone, which they say creates instability in a regional neighborhood already fueled by anxiety.
Biden stressed this point Tuesday during his meeting with Japanese Prime Minister Shinzo Abe. Japan is one of the U.S.'s staunchest allies and a major recipient of U.S. military aid.
"The U.S. and Japanese security liaison is the cornerstone not merely in the Pacific region but the cornerstone on which our security is built for the next 20 years," said Biden during the talks with Abe, according to the Japan Times.
"This action has raised regional tensions and increased the risk of accidents and miscalculation," Biden said, according to the Asahi Shimbun. "I will be raising these issues with great specificity when I meet with Chinese leadership the day after tomorrow."