"I think he will go tomorrow or Friday," said the official, without giving details.

Wu, chairman of the National People's Congress, was expected to raise with high-ranking North Korean leaders an 11-month crisis over the Stalinist country's nuclear development program.

He would be the highest-ranking Chinese leader known to visit China's closed-off neighbor in recent years and someone of his position would likely be received by the North Korean leader, Kim Jong-Il.

Sending an official of Wu's stature indicates Beijing's determination to help the United States resolve the standoff between Pyongyang and Washington over the North's ambitions to develop nuclear weapons.

Analysts said Beijing, while initially reluctant to play an active role in resolving the dispute, now realizes the necessity of helping to broker a resolution, given the threat posed to China by a nuclear-armed North or by potential military conflict between Pyongyang and Washington if the situation deteriorates.

Beijing is also eager to gain benefits from Washington, such as improved Sino-US relations, by helping the United States convince Pyongyang to give up its nuclear ambitions, analysts said.

Wu's mission will be part of Beijing's efforts to encourage a new round of multilateral nuclear negotiations with North Korea after six-nation crisis talks ended inconclusively in Beijing last month.

The last high-ranking Chinese officials to visit North Korea were Vice Foreign Minister Dai Bingguo, who was there in July -- a month before the six-nation talks, and Vice Foreign Minister Wang Yi, who was there in early August to discuss preparations for the talks.

Another foreign ministry official had told AFP last week that Wu would be traveling to North Korea soon, but did not specify a date.

"He is going soon and the visit will be announced before he goes," the official said.

China and North Korea often keep their high-level exchanges secret, including visits by the North's strongman Kim whose two visits to Beijing in recent years were only announced after they were completed.

A former Chinese vice premier and retired senior diplomat, Qian Qichen, reportedly made a secret visit to Pyongyang earlier this year to cement three-party talks between North Korea, the United States and China in April.

Chinese officials have continued to refuse to confirm that visit, but do not deny that it may have taken place.

WAR.WIRE