China firmly opposes disruption of the legitimate activities of Chinese research vessels by Japan and has lodged serious protests with the country, Chinese foreign ministry spokesperson Mao Ning said on Tuesday.

A file photo of the Diaoyu Dao in the East China Sea, September, 2012. (Photo: VCG)

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

"China firmly opposes Japan's disruption of the legitimate activities of Chinese research vessels and has lodged serious protests with the Japanese side," Mao said.