The Chinese Foreign Ministry on Monday condemned a move by Japan's Ishigaki City to change the name of the Diaoyu Islands, calling it a "serious provocation on China's territorial sovereignty." 

The Ishigaki Municipal Assembly on Monday approved a proposal to rename an "administrative area" containing the islands from "Tonoshiro" to Tonoshiro Senkaku." 

"The Diaoyu Islands and its adjacent islets have always been an inherent part of Chinese territory, and China has unshakable will to protect its own sovereignty," Chinese Foreign Ministry spokesperson Zhao Lijian said at a regular press briefing. 

The move by the Japanese side is a "serious provocation on China's territorial sovereignty" and is "illegal and invalid," Zhao stressed, adding that it will not change the fact that the Diaoyu Islands belong to China. 

China firmly opposes the move and has lodged solemn representations to Japan through diplomatic channels, he noted. 

Beijing "reserves the right to take further measures in response," he said. 

Zhu Fenglian, spokesperson for the Taiwan Affairs Office of the State Council, also commented on the issue on Monday. Both the Chinese mainland and Taiwan belong to one China, she said in a statement, calling for joint efforts to maintain national sovereignty and territorial integrity.

Read more: China urges Japan to stop illegal activities near Diaoyu Islands

(Cover: Diaoyu Islands and nearby islands seen from a B-3837 marine surveillance plane, December 13, 2012. /Xinhua)