BEIJING, Oct. 1 (Xinhua) -- A Chinese Foreign Ministry spokesman on Friday called for concerted efforts from Japan to maintain relations between the two countries.

Foreign Ministry spokesman Ma Zhaoxu made the remarks following Japanese Prime Minister Naoto Kan's policy speech Friday, in which he reiterated Japan's territorial claim over the Diaoyu Islands.

Ma said the Diaoyu islands and its adjacent islets have been Chinese territory since ancient times.

Japan illegally detained Chinese fishermen and seized ship in waters off the Diaoyu Islands and insisted on performing a so-called domestic judicial procedure. Such moves were "absurd, illegal and invalid," Ma said.

As a neighbor of Japan, China has always attached importance to developing bilateral ties with Japan, Ma said.

"I hope Japan will work with China to jointly maintain relations between the two countries," Ma said.

In the speech at the opening of an extraordinary Diet session on Friday, Naoto Kan also said amicable ties between Japan and China were vital not only for the two nations but also for the peace and stability in the Asia-Pacific region.