BEIJING (Reuters) - China said on Monday it reserves the right to respond to a Japanese city's decision to rename the administrative area that includes remote islands claimed by both China and Japan and have long been a source of friction between the neighbours.
The row over the uninhabited East China Sea islets may add to recent tension caused by Japan's criticisms of Beijing's plan to impose a new national security law in Hong Kong.
China has said Japan should not interfere in Beijing's internal affairs.
The disputed islands are known as the Senkaku in Japan and the Diaoyu in China.
Japanese broadcaster NHK reported earlier that the Ishigaki City assembly in Okinawa, in southern Japan, had passed a bill to change the name of the administrative area covering the islands to Tonoshiro Senkaku from Tonoshiro, from Oct. 1.
The bill was "a serious provocation to China's territorial sovereignty, is illegal, invalid, and cannot change the fact that the Diaoyu Islands belong to China", the Chinese foreign ministry said.
"China's resolve and determination to protect its territorial sovereignty is unwavering," ministry spokesman Zhao Lijian told reporters at a daily briefing.
China has lodged a complaint with Japan and reserved the right to take further action, Zhao said.
NHK said the name had been changed to avoid administrative mistakes as another location in Ishigaki City was also called Tonoshiro.
It came at a time that Chinese coastguard vessels had been repeatedly intruding into Japanese waters near the islands, NHK said.
Japan's Chief Cabinet Secretary Yoshihide Suga said last week Japan would take all measures to ensure surveillance of the areas around the disputed islands.
Taiwan's government, which also claims the islets, also said its foreign ministry had "strongly protested" to Japan about the name change.
(Reporting by Gabriel Crossley; additional reporting by Ben Blanchard in Taipei; writing by Se Young Lee; editing by Louise Heavens)