Wi Sung-lac, Special Representative for Korean Peninsula Peace and Security Affairs, has left for the United States Wednesday to discuss the denuclearization of the Democratic People's Republic of Korea (DPRK) and ways to resume the six-party talks. During his four-day trip, Wi is scheduled to meet with Kurt Campbell, U.S. Assistant Secretary of State for East Asian and Pacific Affairs, Stephen Bosworth, U.S. special envoy to the DPRK, and Jeffrey Bader, U.S. President Barack Obama's top advisor on Asian Affairs, according to the Ministry of Foreign Affairs and Trade. 'There will be discussions on how to deal with the DPRK's recent demand for a peace treaty and lifting of sanctions for their return to the six-party talks, as well as an evaluation of U. S. special envoy Bosworth's visit to the DPRK last year,' a ministry source was quoted as saying by the Yonhap news agency. As part of an effort to bring the DPRK back to the talking table, Bosworth paid a three-day visit to Pyongyang last December where both parties recognized the need to resume the six-party talks. However, the DPRK on Monday demanded a negotiation for a peace treaty and lifting sanctions before returning to the nuclear disarmament talks. 