BEIJING – China firmly opposes Japan's disruption of the legitimate activities of Chinese research vessels and has lodged serious protests to the Japanese side, the Chinese Foreign Ministry said on Tuesday.

Noting that Diaoyu Dao and its affiliated islands are China's inherent territory, ministry spokeswoman Mao Ning 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.