TOKYO - The Japanese government has reached an agreement with the family, who claims to own the Diaoyu Islands, to buy the islands, local media reported Wednesday.

Kyodo reported that the central government has reached an agreement to pay 2.05 billion yen ($26.15 million) for the purchase of part of the chain of the islands in the East China Sea.

Tokyo Governor Shintaro Ishihara has announced in April that the Tokyo government plans to purchase three of the five uninhabited islands.

A survey group organized by Tokyo metropolitan government arrived at waters near Diaoyu Islands and started illegal survey around the islands Sunday morning.

Chinese Foreign Ministry spokesman Hong Lei said Monday that China has lodged a solemn representation to Japan over the survey conducted by the Tokyo government in waters near the Diaoyu Islands.

"Any unilateral action by Japan regarding the Diaoyu Islands is illegal and invalid," Hong Lei said at a routine press briefing.

Hong stressed that the Diaoyu Islands have been China's inherent territory since ancient times, adding that China holds indisputable sovereignty over the islands.

China has urged Japan to handle the recent problems properly to avoid any harm of the China-Japan ties.