Vice-President Joe Biden will raise the United States' concerns with China's leaders and seek clarity on their intentions in setting up an Air Defence Identification Zone (ADIZ) during his three-nation Asian tour next week.
While Washington has called the new zone destabilising, senior administration officials stressed that Mr Biden will not be in Beijing to deliver a demarche, but to make the broad point that an "emerging pattern of Chinese behaviour" is unsettling neighbours.
Defence Secretary Chuck Hagel, in a phone call to Japanese Defence Minister Itsunori Onodera on Wednesday, said the new zone "raises the risk of misunderstanding and miscalculation".
The ADIZ announced last Saturday overlaps part of Japan's zone and covers disputed islands in the East China Sea known as Senkaku to the Japanese and Diaoyu to the Chinese.
Besides praising Tokyo's restraint, Mr Hagel also assured its ally that the US-Japan security pact covers the disputed islands.
With the new zone, all aircraft passing through it must submit their flight plans to the Chinese.
That requirement was tested early this week when two unarmed US B-52 bombers crossed the zone unannounced.
Tokyo also instructed its commercial carriers not to comply with the new rules.
Senior administration officials said China's move raised a num- ber of questions, and Beijing needs to "clarify its intentions".
"We are talking about international airspace. We are not talking about over-flights of sovereign territory, and so there is legitimate interest by the United States, as well as by the international community," a senior official said during a conference call on the Vice-President's trip to China, Japan and South Korea.