BEIJING, Aug. 7 -- Several Japanese aircraft entered China's Air Defense Identification Zone (ADIZ) over the East China Sea on Wednesday and carried out extensive reconnaissance, according to the Chinese Air Force.

Chinese planes conducted necessary tracking and monitoring of the foreign military planes, said Chinese Air Force spokesman Shen Jinke on Thursday.

The Japanese F-15 aircraft twice attempted to approach Chinese patrol planes that were conducting a routine patrol in the ADIZ, and the Chinese planes took reasonable, proper and restrained measures to cope with the threat in the airspace, Shen said.