It will take time to move the deadlocked North Korea nuclear talks forward because Pyongyang must reverse its previous denial that it sought to enrich uranium, South Korea's top nuclear envoy said Wednesday. The North agreed in October to disable its nuclear facilities and provide a declaration of its nuclear programs by the end of 2007. However, the process has come to a standstill because the US says the North has yet to provide a complete list. "The issue of declaration is a difficult one in its essence," South Korean nuclear envoy Chun Yung-woo said at a news conference marking the first anniversary of the landmark deal. For Pyongyang to account for its nuclear programs, "it would take time and efforts as (the North) has to change its previous claims," he said.