China on Saturday lodged solemn representations with Japan as some Japanese lawmakers and members of right-wing groups plan to go to the Diaoyu Islands waters to hold activities.

Foreign Ministry Spokesman Qin Gang said that China has urged the Japanese side to immediately stop the action that seeks to undermine China's territorial sovereignty.

Any unilateral action taken by Japan on the Diaoyu Islands is illegal and invalid, Qin said, stressing that Japan's unilateral actions will not change the fact that the Diaoyu Islands are China's inherent territory.

Some Japanese lawmakers and members of right-wing groups plan to go to the Diaoyu Islands waters to mourn war dead in World War II Saturday evening.