Chief Cabinet Secretary Kato Katsunobu told reporters on Monday that Japan has filed a protest via diplomatic channels, calling for the website to be taken down. He said Japan controls the islands, while China only claims them.

The Japanese government insists that the islands are an integral part of Japan's territory, in terms of history and international law, and there is no issue of sovereignty to be resolved.

Kato said China has no right to create such a website about Japanese territory, and called Beijing's claims unacceptable.