South Korea\'s top nuclear envoy Lim Sung-nam left for the United States Monday to attend the first three-way talks with senior officials from Washington and Tokyo since the death of Kim Jong-il. Lim Sung-nam, the chief South Korean envoy to the six-party talks on North Korea\'s nuclear weapons program, will hold the talks on Tuesday with his Japanese counterpart Shinsuke Sugiyama and Kurt Campbell, Washington\'s top diplomat on Asia, South Korea\'s news agency (Yonhap) reported.