A Foreign Ministry spokesman on Friday expressed China's "grave concern" and "strong displeasure" over the "highly irresponsible remarks" made by Japanese Prime Minister Yoshihiko Noda regarding the Diaoyu Islands.

"Nothing can shake China's firm resolve and determination to safeguard its territorial sovereignty," spokesman Hong Lei said, adding that the Diaoyu Islands and its affiliated islands have been part of China's inherent territory since ancient times.

China has taken note of the willingness expressed by Japan to solve the issue through diplomatic efforts, Hong said.

"Japan should make concrete efforts to properly solve relevant issues while fully considering the overall condition of Japan-China relations," Hong said.

Previous media reports stated that Noda said the Japanese government would use force if necessary to resolutely respond to any illegal activity that occurs within Japan's borders, including the "Senkaku Islands," as the Diaoyu Islands are referred to in Japan.