U.S. diplomats say they do not plan a formal meeting alone with Pyongyang's negotiators. The six countries at the talks have given little indication of whether any progress is being made.

Although U.S. negotiators held an unexpected private discussion with North Korea's delegation on the first day of talks, American diplomats say there will be no formal bilateral meeting between the two teams.

The comment Thursday from U.S. Embassy officials in Beijing came shortly before the start of the second day of six-nation talks on the North Korean nuclear crisis. The two teams met for about 30 minutes Wednesday at the side of the first session of talks.

The United States, North Korea, South Korea, China, Japan and Russia are taking part in the three-day talks. U-S officials say Pyongyang's efforts to build nuclear weapons is a multilateral concern and refuses to hold formal private talks with North Korea on the matter.

The delegates have revealed little of what has been discussed so far, although South Korean and Chinese officials have said the talks went smoothly.

Russia's chief negotiator, Deputy Foreign Minister Alexander Losyukov, called the situation fragile and said he does not feel great optimism because of the gap between the U.S. and North Korean positions.

"How soon we would be able to remove mistrust and remove that gap of trust which exists between them (NK) and Americans, I don't know. It takes long negotiations and we hope that the process of negotiations which have just been started in Beijing could be continued," he said.

This mistrust was underscored by North Korea's official Rodong Sinmun newspaper, seen on the Internet Thursday, which repeated Pyongyang's accusations that the United States is preparing to attack it.

The crisis began in October, after Washington said Pyongyang was developing nuclear weapons, in violation of international accords. North Korea has since confirmed that it has a nuclear program and has withdrawn from the global nuclear Non-Proliferation Treaty.

The five other countries at the Beijing talks want North Korea to abandon the weapons program. Pyongyang first wants a formal non-aggression pact from the United States. Washington says it will not sign such a document, but will offer written assurance that it has no plans to attack North Korea.

Analysts say the fact that the North Koreans have not walked out of the talks is already a good sign, and that one marker of success would be an agreement to meet again. The talks wind up Friday.