The Obama administration has dispatched a team of experts to Asian capitals to report that North Korea appears to have started a program to enrich uranium, possibly to manufacture more nuclear weapons, a senior U.S. administration official said Saturday.

The team was sent out after North Korea told two visiting American experts earlier this month that it possessed such a program and showed them a facility where it claimed the enrichment was taking place.

"North Korea's claim to have a uranium enrichment program is yet another provocative act of defiance and, if true, contradicts its own pledges and commitments," the senior administration official said.

"We have long suspected North Korea of having this kind of capability, and we have regularly raised it with them directly and with our partners in this effort," the official said.

The claim of the facility's existence - made to Siegfried Hecker, the former chief of the Los Alamos National Laboratory, and former U.S. government analyst Robert Carlin - complicates the Obama administration's efforts to counter nuclear proliferation around the globe. It also raises questions about North Korea's motivations in announcing the presence of the plant as it undertakes a leadership transition from leader Kim Jong Il, apparently to his third son, Kim Jong Eun.

North Korea's disclosure of this facility was first reported by the New York Times on its Web site Saturday.

The North Koreans told Hecker that the facility - located at Yongbyon, where North Korea once had a program to isolate plutonium for nuclear weapons - was for the low-enriched uranium generally used in power plants, according to David Albright, the director of the Institute for Science and International Security, which has monitored North Korea's nuclear programs for years.

But Albright said he thinks the program could be used to produce weapons-grade, highly enriched uranium. North Korea's nuclear arsenal has so far used plutonium recovered from spent nuclear reactor fuel rods, the other way to obtain weapons-grade fissile material.

In October, Albright's group reported that North Korea "has moved beyond laboratory-scale work" and is capable of building a "pilot plant" of centrifuges to enrich uranium.

The senior U.S. official said that North Korea's policy of using "missiles and nuclear tests to threaten the international community and extract concessions . . . hasn't worked because of strong unity among allies."

Still, there is debate among the nations involved in the stalled six-party talks on North Korea's nuclear program - South Korea, Japan, the United States, Russia and China. Beijing has advocated that the talks resume because, it says, if North Korea is involved in talks, it will be less likely to lash out at the West or conduct another nuclear test. a third nuclear test. (North Korea is thought to have tested a nuclear device in 2006 and again in 2009.) Some officials in Washington, Seoul, Tokyo and Moscow agree with the Chinese position.

Nonetheless, many in the Obama administration and in other capitals are wary of being drawn into the same pattern with North Korea that bedeviled previous U.S. administrations and other governments - wherein Kim Jong Il's government made threats and then was rewarded with cash and other benefits not to carry them out.

"We have consistently insisted that any talks must be real negotiations over its nuclear weapons program," the senior official said in an e-mail.