Two prominent experts on North Korea who recently made an unpublicized visit to the reclusive nation briefed Secretary of State Condoleezza Rice yesterday as U.S. negotiators prepared to return to Beijing for a renewal of six-nation disarmament talks.

China announced yesterday that the talks would resume next Tuesday, after a recess of more than five weeks after the participants were unable to reach agreement on a "statement of principles" that would guide negotiations to eliminate North Korea's nuclear programs. Japan, South Korea and Russia are also participants in the talks.

John W. Lewis, a retired Stanford University professor, and Siegfried S. Hecker, retired director of Los Alamos National Laboratory, met with Rice yesterday afternoon to provide details of their talks with key North Korean officials, including the top negotiators for the North Korean side.

The two men summarized their conversations in Pyongyang, made some suggestions for bridging gaps, and provided an assessment of the chances of reaching an agreement, according to one U.S. official.

During the talks with Lewis and Hecker, North Korean officials made it clear that they intend to insist that the statement of principles acknowledge North Korea's right to peaceful use of nuclear power, according to Charles L. "Jack" Pritchard, a former State Department Korea expert, who accompanied the two men.

To varying degrees, South Korea, China and Russia have supported the North Korean position, while Japan has backed the U.S. stance that North Korea's behavior gives it no right to even a peaceful program, except for research for medical, agricultural or industrial use.

"The North Koreans saw a chink in the armor," Pritchard said. "They have concluded this is a winning argument."

Pritchard said that as a result, any statement emerging from the talks appears less likely to be as clear and definitive as U.S. officials had hoped. This in turn might drag out future negotiations.

To prod North Korea to return to the talks, Rice had declared that the United States recognized North Korea's sovereignty. From the North Korean perspective, a sovereign nation has a right to peaceful nuclear energy, and one way the United States can demonstrate that it respects North Korea's sovereignty is to support that right.

North Korea's position -- which also included a demand for a light-water reactor to compensate it for giving up its current nuclear facilities -- has led to sometimes heated discussions within the Bush administration over how to counter Pyongyang's gambit, U.S. officials said.

Some officials, such as Assistant Secretary Christopher R. Hill, the chief U.S. negotiator, have contended that the issue of whether North Korea has a theoretical right to peaceful nuclear energy is not as important as the main question of whether an agreement to eliminate North Korea's nuclear programs can be reached in the first place. Moreover, even if North Korea wanted to build a civilian nuclear program, none of the countries at the table now would even be willing to fund it.

"The issue for some of the partners is whether . . . North Korea could then reclaim a right to nuclear energy," Hill said last month. "If you ask me, it's not exactly a showstopper issue -- the real issue is getting rid of all their nuclear programs."

But other officials have pushed back, saying that such a concession would allow the North Koreans to chip away at an agreement, especially if they managed to hide materials or programs not discovered during the verification process.

Some of the internal debate has centered on arcane and detailed discussion over various articles of the nuclear Non-Proliferation Treaty. Some argue that the first two articles support a theoretical right, but others argue that that hinges on compliance with the fourth article, which requires a country to live up to its obligations. North Korea has violated those obligations and withdrawn from the treaty.

Some conservatives in the administration, however, believe the administration has weakened its position in the North Korean talks by agreeing to support the European negotiations with Iran on its nuclear programs, and by quickly reaching a deal this year with India to supply it with civilian nuclear energy. Iran has violated the Non-Proliferation Treaty, and India never joined it.