BEIJING, July 7 (Xinhua) -- China firmly opposes Japan's disruption in the legitimate activities of Chinese research vessels and has lodged serious protests to the Japanese side, Chinese foreign ministry spokesperson Mao Ning said on Tuesday.

Noting that Diaoyu Dao and its affiliated islands are China's inherent territory, Mao said at a regular news briefing that Chinese research vessels' activities in the waters adjacent to the Diaoyu Dao are matters under China's sovereign rights, which are legitimate, lawful, and beyond reproach.