China is up in arms about Japan’s attempt to name a group of uninhabited islets near the Diaoyu Islands, which stand at the center of a territorial dispute between the two countries.

China’s official People’s Daily newspaper said Tuesday that Japan should not test China’s "firm and unwavering" determination in safeguarding its sovereignty over the Diaoyu Islands. The Chinese daily added that naming the nearby uninhabited islets is an act that hurts the core national interest of China.

The newspaper also quoted Chinese Foreign Ministry spokesman Liu Weimin as saying China has indisputable sovereignty over the Diaoyu Islands that have been an inherent part of China since ancient times.

Japanese Chief Cabinet Secretary Osamu Fujimura recently announced plans to name 39 islets near the disputed islands, which are known as Senkaku in Japanese.