Washington's top-ranking diplomats on Asia and arms control are in Beijing, hoping to enlist China in a diplomatic offensive against North Korea's just-revealed nuclear weapons program.
James Kelly, the assistant secretary of state for East Asia, and John Bolton, the State Department's arms control chief, have been in Beijing for two days, meeting with Chinese officials.
The U.S. Embassy released no details, but Bush Administration officials say they are hoping to enlist several key nations - including China - in an international effort to pressure North Korea to renounce its program of developing nuclear weapons.
The meetings follow North Korea's admission that it has continued its nuclear program, despite an agreement it signed with the U.S. to stop such work.
President Bush called the news "troubling and sobering," and analysts say the issue is certain to come up at Mr. Bush's summit meeting next week with the Chinese President, Jiang Zemin.
Beijing's help would be valuable in the effort, because China is one of North Korea's few friends.
Earlier, China's Foreign Ministry called an allegation that Beijing had exported nuclear technology to North Korea "nonsense."
Foreign Ministry spokeswoman Zhang Qiyue says China supports a nuclear-free Korean peninsula, and expressed the hope that the tensions over the North Korean project can be resolved through peaceful dialogue.
North Korea's admission that it is still working on nuclear weapons caused deep concern in Washington, South Korea, Japan, and elsewhere, partly because Pyongyang has also developedand tested missiles that could carry nuclear devices to distant cities.