A US-Japanese plan to deal with a possible military conflict across the Taiwan Straits has caused "grave concern" in Beijing.

Washington and Tokyo will discuss a contingency plan in case of a "crisis" situation arising in areas around Japan, including the Taiwan Straits, Kyodo News Agency reported yesterday.

The report quoted several sources familiar with Japan-US military cooperation as saying the two sides have reached consensus on the necessity for such a contingency plan and will soon begin discussing the details.