TOKYO - The annual Tokyo Defense Forum kicked off Wednesday in Tokyo without China's participation this year.

"We were at first hoping to exchange some views with China during this international forum... But they didn't come," Japan's Minister of Defense Satoshi Morimoto told reporters after he gave an opening remark at the forum.

Japanese media earlier reported that the absence of China this time was caused by territorial tensions between the two countries.

During the opening speech, Morimoto said the forum will further discuss the US role in the region in response to challenges and called on countries in this region to cooperate to face new security challenges and maintain the region's peace stability.

Tokyo Defense Forum has been annually held by Japan's Ministry of Defense since 1996.

The purpose of the TDF is to contribute to the stability of the Asia-Pacific region by providing a forum of candid exchange of views for senior defense officials in charge of policy or defense exchanges in the region, according to Japan's Ministry of Defense.