China and Taiwan criticised Japan for giving Japanese names to disputed islands in the East China Sea claimed by all three parties in a long-running diplomatic row.
China and Japan have a lengthy dispute over an uninhabited but strategically coveted island chain known as Diaoyu in Chinese and Senkaku in Japanese.
Taiwan also claims the islands and local activists have tried to sail to the disputed area to press Taipei's claim. China's foreign ministry on Saturday said moves by Japan to rename scores of islands in the chain was "illegal and invalid", according to a statement posted on the ministry's website. (AFP)