The government has started reviewing the guidelines for defense cooperation with the United States to address new security challenges such as terrorism, the threat of weapons of mass destruction and military developments in North Korea and China, government sources said Sunday.

Ahead of updating the Guidelines for Japan-U.S. Defense Cooperation, Tokyo and Washington are also hoping to hold a summit by autumn to produce a joint statement on security or a similar agreement document, the sources said.

The update, intended to define the role of the two countries for closer cooperation in light of the new challenges, will be the first since 1997 when they issued the current defense guidelines.

The government is aiming to effect the revision by the end of 2006 by conducting informal consultations with the U.S. government concurrently with bilateral discussions on the realignment of the U.S. forces in Japan, the sources said.

The review focuses on possible areas of cooperation in international activities, including counterterrorism measures and assistance for reconstruction in Iraq, as well as a policy on joint operations should an incident occur in the Taiwan Strait, the sources said.

Another topic under review is a reappraisal of the three categories of bilateral cooperation: during peacetime, during an armed attack on Japan and in an emergency in "areas surrounding Japan." Support by the Self-Defense Forces for the U.S. military in Japan is also on the table.

The sources said it remains to be seen whether Japan and the U.S. will be able to produce a statement at the summit later this year, but they are hoping to redefine the roles of the SDF and the U.S. armed forces.