China's Vice Premier Li Keqiang departed for North Korea Sunday, state television said, amid hopes for progress on restarting stalled six-nation talks on the North's nuclear disarmament.
Li, who is tipped to take over as China's premier next year, was accompanied by officials from China's foreign and commerce ministries, the report said, but gave no details about the agenda for the trip.
China is Pyongyang's closest ally and a major economic partner.
The official visit is scheduled to last until Tuesday, China's foreign ministry said.
Afterwards Li, who is expected to succeed Wen Jiabao as part of a leadership transition, is due to visit South Korea, North Korea's arch-rival.
South Korea's foreign ministry has said that discussions during the two-day visit will focus on the Korean peninsula where China is pressing to restart stalled six-nation talks on the North's nuclear disarmament.
China has hosted the forum, which includes the two Koreas, Russia, the United States and Japan, since 2003.
South Korea, supported by the US and Japan, says the North must take steps to show it is serious about scrapping its atomic arsenal before the six-nation talks can resume.
The US and North Korea are due to meet in Geneva on Monday for their second round of direct talks aimed at reviving the long-stalled nuclear disarmament negotiations