The Foreign Ministry said on Friday that Japan's unilateral decision to name China's Diaoyu Islands was "invalid" as it persisted in fueling lingering territorial tensions.

Japan infuriated China and damaged ties two years ago when it said it was "nationalizing" the islands in the East China Sea, which have been part of China's traditional territory and an important fishery for centuries.

The Japanese Cabinet announced on Friday afternoon that the government had given names to "158 unnamed remote islands", including islands in the Diaoyu group.