New U.S. Ambassador Caroline Kennedy on Wednesday criticized China's move to set up an air defense identification zone in the East China Sea covering the Senkaku islands, stressing that unilateral actions like this elevate tensions.

In her first public speech as ambassador, the soft-spoken Kennedy also voiced support for Japan's efforts to bolster security measures, such as establishing a national security council as soon as next week.

"Unilateral actions like those taken by China with their announcement of an East China Sea air defense identification zone undermine security and constitute an attempt to change the status quo in the East China Sea. This only serves to increase tensions in the region and create unnecessary risk," Kennedy said at a welcome luncheon in Tokyo hosted by the America-Japan Society and the American Chamber of Commerce in Japan.