China's failure to assertively pursue a solution to the crisis over North Korea is irritating the United States and South Korea, threatening to undermine progress in U.S.-China relations since the Sept. 11, 2001, terrorist attacks, U.S. and Asian officials said.

Beijing's diplomatic reluctance has also prompted unease among Chinese scholars and officials who noted the gap between China's ambition to be a major player in Asia and its failure to move swiftly to deal with the brewing crisis on its border. The crisis was set off by North Korea's acknowledgment that it has a program to develop material that can be used to make nuclear weapons.

An American official described the U.S. reaction as "bewildered" rather than angry at China's refusal to send a delegation to Pyongyang. But other U.S. officials reiterated that this increasingly has become a sore point. U.S. envoys to Beijing have stressed that for 50 years the United States has helped keep Japan, South Korea and Taiwan from acquiring nuclear power, and now it is China's turn to return the favor, another American said.

"But that line seems to fall flat in Beijing," he said. "They seem to want the crisis to go away."

A South Korean official said Beijing snubbed a request from Seoul that China send a delegation to Pyongyang to express concerns to the government of Kim Jong Il. "They don't look at the nuclear issue as the biggest issue," he said. "Their main goal is to help North Korea get stronger."

China has watched from the sidelines as first Russia and then Australia dispatched envoys to North Korea. Beijing's pronouncements on the issue have been generally limited to opposing the development of nuclear weapons on the Korean Peninsula and urging the United States to talk with North Korea.

"There's a saying in Chinese, 'a lock can only be opened by one key,' " the Foreign Ministry spokeswoman, Zhang Qiyue, said late last month in response to a question. "I think as long as the relevant sides feel that the resumption of direct dialogue between the United States and North Korea is the crux of the matter, then I think all concerned parties should continue to make efforts to push them to resume talks."

Chinese officials also argued that China has limited influence over North Korea. However, U.S. and South Korean officials rejected that claim.

China is the North's most important trading partner, they noted. Trade with North Korea hit more than $700 million in 2002, up 30 percent over 2001. With the recent cutoff of U.S. fuel supplies to Pyongyang, China is now believed to supply about 70 percent of the North's oil, experts said. China has also doubled its sales of grain and vegetables.

China's handling of the crisis has also touched off a debate in Chinese foreign policy circles and within the government and the military, Chinese sources said. One senior Chinese official said the debate is part of a broader struggle between younger Chinese officials who believe China should take a greater role in international affairs and more conservative officials who believe China should focus on economic development and that the North Korean government should be propped up no matter what.

An influential faction has the primary goal of bolstering North Korea, fearing that the North's sputtering economy could lead to collapse. That would bring about the end of the buffer state between China and South Korea, home to 37,000 U.S. troops. It would also mean that South Korea, which has invested billions in China, would be forced to devote all its resources to uniting with the North.

This faction, according to the South Korean official, looks at the current crisis as a way to help Pyongyang improve its economy and international standing, through a security guarantee from Washington and access to World Bank loans and other investment.

The Chinese official said Beijing has engaged in a flurry of diplomatic activity with Pyongyang but only a few meetings have been publicized. He said Foreign Minister Tang Jiaxuan, Vice Foreign Minister Wang Yi and other Foreign Ministry officials have met with North Korean diplomats on numerous occasions in Beijing to convey China's concerns. Chinese diplomats in Pyongyang have done the same, he said.

"You could argue that we are even more active than the Russians," he said.

However, he acknowledged that the Korean affair has underscored a Chinese weakness in dealing with crises and the need in Beijing for some type of national security council to develop a concerted response to such events. The need for such an organization has been debated for years. Most Chinese officials now appear to accept its usefulness. The current debate revolves around whether the council will be run by the Communist Party or the State Council or some other body.

The official and other sources also argued that the conservative nature of Chinese diplomacy makes it difficult for Beijing to play a role in resolving any crisis. "We generally only propose things that we are sure will be accepted," he said. "That makes it difficult for us to be involved in the solution of any crisis. We need to learn that the important thing is not the proposal but the process that leads to a solution."

So far China's only public proposal has been to offer to host talks in Beijing.

Kessler reported from Washington.