BEIJING - China said on Saturday it firmly opposes Japan's naming of the Diaoyu Islands.

The remarks came after Japanese cabinet released names of 39 uninhabited islands, including some isles affiliated to the Diaoyu Island, on Friday.

"I would like to reiterate that any unilateral action taken by the Japanese side about the Diaoyu Island and its affiliated isles is illegal and invalid," Chinese Foreign Ministry Spokesman Hong Lei said in a written statement.

The Diaoyu Island and other related isles have been part of inherent Chinese territory since ancient times, and China has indisputable sovereignty over them, Hong said.

"No matter what names Japan has given to the isles affiliated to the Diaoyu Island, it will not change the fact that these islands belong to China," he said.

The spokesperson suggested those who want to know the Diaoyu Islands' standard names should visit websites of the Ministry of Civil Affairs and the State Oceanic Administration.