Japan has begun studying the feasibility of easing rules on the use of weapons by Self-Defense Forces troops taking part in logistic support for the expected U.S. military operation against terrorism, government sources said.

The government is considering allowing troops to use weapons when deemed "necessary to carry out duties" under a soon-to-be-submitted bill authorizing the SDF to provide logistic support to U.S. military action against the terrorists connected with the Sept. 11 attacks in the United States, they said Saturday.

The government previously envisioned allowing the troops to only use weapons to protect themselves and their colleagues, a restriction imposed by existing laws on troops taking part in U.N. peacekeeping operations or logistic support of U.S. forces in the event of an emergency in "areas surrounding Japan."