The United States and Japan agreed Saturday to strengthen the U.S. defense of its top ally against a nuclear attack by North Korea _ Japan's top security concern. The U.S. has established a «nuclear umbrella» to protect Japan and other non-nuclear allies from possible attack. U.S. and Japanese officials in charge of defense and foreign affairs decided Saturday to hold regular talks on how to boost the effectiveness of the defense system, a Japanese Foreign Ministry official was quoted as saying by the Associated Press. They also agreed to increase efforts to encourage North Korea to return to international disarmament talks. U.S. delegates Kurt Campbell, Assistant Secretary of State for East Asian and Pacific Affairs, and Assistant Secretary of Defense Wallace Gregson completed the bilateral talks Saturday with Japanese counterparts Kazuyoshi Umemoto, Foreign Ministry director general of North America, and Nobushige Takamizawa, Defense Ministry director general.
