A U.S. envoy was in Beijing on Thursday to discuss with Chinese officials the U.N. sanctions imposed on North Korea for a nuclear test conducted in May, according to AP. Philip Goldberg, a former ambassador who is in charge of coordinating the implementation of sanctions against the North, will meet with representatives from the Foreign Ministry and other relevant ministries, the U.S. Embassy said. China is Pyongyang's closest ally and largest source of fuel and food aid, and its cooperation in enforcing sanctions against its neighbor is seen as crucial to increasing pressure meant to push North Korea back to nuclear disarmament talks that have stalled. A new U.N. resolution seeks to stop North Korea's trading of banned weapons by requiring U.N. members to request inspections of ships suspected of carrying prohibited cargo. A North Korean ship came under intense scrutiny for more than a week by the U.S. Navy as it was detected heading toward Myanmar with suspicious cargo aboard. On Sunday, the Kang Nam 1 then turned around and headed back north, U.S. intelligence officials said Tuesday. It was unclear what the ship's turnaround means, nor what prompted it. The ship was the first vessel monitored under the U.N. sanctions. Pyongyang has said that any interception of its ships would be considered a declaration of war. China is sending its own envoy, Vice Foreign Minister Wu Dawei, on an extended trip to Russia, the United States, Japan and South Korea to talk about the Korean nuclear situation and how to restart the six-party disarmament talks. Wu left Beijing Thursday, the Foreign Ministry confirmed «The purpose of Wu Dawei's visit is to exchange views with relevant parties on the nuclear issues on the Korean peninsula and the situation in northeast Asia,» said ministry spokesman Qin Gang at a regularly scheduled press conference.