Japan's Defence Ministry has confirmed the Liaoning and Shandong operating in separate locations in the Pacific on Saturday, both near remote southern islands belonging to Japan.
Iwaya said the ministry had communicated with Beijing through China's embassy in Japan and that it would take further "appropriate steps" as needed. He stopped short of condemning China for the operations.
Japan had said a day earlier that Liaoning sailed in the sea within Japan's exclusive economic zone near Minamitorishima, a remote island east of Iwo Jima.