TOKYO, Nov. 14 (Xinhua) -- Japan and its ally the United States on Thursday began discussing the revision of bilateral defense guidelines in a meeting involving their senior defense and diplomatic officials, local media reported.

Responding to cyber-attacks and cooperation in using outer space are believed to have been covered in a director-general level meeting, but it was the first time that the two sides work on revising the defense guidelines, said Japan's Kyodo News.

Japan and the United States agreed last month in their "two- plus-two" meeting involving their defense and foreign chiefs to revise the guidelines by the end of 2014.

The guidelines specify role-sharing between the Japanese Self- Defense Forces and the U.S. military forces in defending Japan.

Koji Tomita, director general of Japan's Foreign Ministry's North American Affairs Bureau, and Hideshi Tokuchi, director general of the Defense Ministry's Defense Policy Bureau attended the meeting on the Japanese side, while James Zumwalt, deputy assistant secretary of state for East Asian and Pacific affairs, and Peter Lavoy, acting assistant secretary of defense for Asian and Pacific security affairs, represented the U.S. side, said Kyodo, citing government officials.