China (search) and the United States (search) disagree over a key part of North Korea's nuclear capabilities, a U.S. official said Friday, a dispute that could give the North Koreans a diplomatic boost in sensitive talks later this month.

China has refused to accept the U.S. contention that North Korea (search) is developing nuclear weapons based on highly enriched uranium (search), the official said. North Korea has acknowledged it has a plutonium-based program but denies it is developing a uranium-based one.

The administration official, speaking on condition of anonymity, said U.S. diplomats have told Beijing its position is not helpful.

American negotiators are concerned that China's stand could benefit Pyongyang (search) heading into six-party talks to be held Feb. 25 in Beijing on the overall North Korean nuclear program.

Besides the United States and North Korea, the discussions also will include China, South Korea, Japan and Russia.

The Bush administration is seeking a complete and verifiable elimination of the North's nuclear capability. Officials have said it is difficult to see how such an agreement can be reached if Pyongyang continues to maintain that it has no uranium program.

The Bush administration says that intelligence information confirmed the uranium program in 2002, and that a senior North Korean official acknowledged its existence in October of that year during a meeting with U.S. diplomats.

But North Korea has since denied making any such statements and apparently is hoping that China, by casting doubt on the U.S. contentions, will help discredit them.

Chinese officials could not immediately be reached for comment Friday.

The Bush administration has frequently praised China for its leadership role in attempts to resolve the North Korea nuclear impasse. Beyond that, China has said it supports the U.S. goal of a Korean peninsula without a nuclear program.

North Korea says it is willing to dispose of its plutonium-based program, the only one it claims to have.

China and the United States have other differences involving North Korea, but they do not appear to be as serious. China, for example, has suggested the United States make concessions in its approach to the North.

It also has been more enthusiastic than the United States over North Korea's willingness to freeze its plutonium-based program.

In December, Secretary of State Colin Powell called that proposal "positive," but the administration has since played down its significance.

State Department spokesman Richard Boucher said last week, "We're not seeking or asking for a freeze. We're looking for elimination of the programs."

Strained U.S. relations with North Korea worsened considerably in 2002 when U.S. officials said intelligence information disclosed a uranium-based program.

U.S. officials said the program violated a 1994 North Korean pledge not to develop nuclear weapons -- part of a broader commitment that also included freezing its plutonium-producing program and placing it under international inspection.

After denying the administration's assertions in 2002, North Korea became increasingly confrontational. Over time, it expelled U.N. nuclear inspectors, withdrew from the Nuclear Non-Proliferation Treaty, restarted an idle nuclear reactor and said it had begun reprocessing spent nuclear fuel rods to produce plutonium.

Multilateral talks in Beijing in April and in August of 2003 on the nuclear impasse were inconclusive. Officials have indicated they expect no major breakthroughs in the talks later this month.

The United States believes North Korea already has one or more plutonium-based nuclear weapons and is concerned that, if left unchecked, the country could develop many more, giving it the potential to blackmail adversaries or export its nuclear technology.