As officials from the six-party talks with North Korea meet in Hanoi on the sidelines of the APEC summit, a U.S. official has told Congress that the burden is on Pyongyang to show it is ready to come to resumed six-party talks next month with a commitment to verifiable elimination of its nuclear weapons program.

U.S. Undersecretary of State for Political Affairs Nicholas Burns says the U.S., China, Japan, South Korea and Russia are united in advance of the hoped for resumption of negotiations.

In recent discussions he and others have had with Chinese officials, Beijing has indicated what Burns calls a great determination to see the September 2005 agreement with Pyongyang implemented.

That is when Pyongyang agreed to eliminate its nuclear weapons programs in exchange for economic cooperation in the form of energy, trade and investment.

Burns says Pyongyang should know there needs to be real progress in the next round of negotiations:

"What we need to do in the next few weeks is to work with the Chinese, the Russians, the Japanese, the South Koreans and all send a common message to the North Koreans," said Nicholas Burns. "When the North Koreans show up at the talks, they have got to deliver this time, and they have to begin to implement this agreement from September 2005, that is very important."

Democratic lawmakers on the House International Relations Committee used Burns' appearance to renew frustration with the Bush administration approach.

Tom Lantos, who will become chairman when Democrats take over the majority in Congress in January, says Pyongyang needs to understand the full consequences of its nuclear test.

However, without what he calls a new approach on the diplomatic front, Lantos fears the next round of negotiations could end in failure:

"Tough new steps against North Korea are not a substitute for a comprehensive and effective new approach toward this seemingly intractable problem," said Tom Lantos. "Heightened diplomacy, including new bilateral overtures, must be part of a new bold approach."

Lantos says those bold steps should include a visit to Pyongyang by chief U.S. negotiator Christopher Hill.

U.S. officials have held bilateral discussions with North Korean officials, but Washington remains committed to a solution under the six-party approach.

In contrast to those who favor putting more incentives on the diplomatic table, Republican Congresswoman Ileana Ros-Lehtinen opposes steps she believes would reward Pyongyang for bad behavior:

"Is our policy now going to be to reward North Korea's behavior by offering to enter into bilateral talks, as some have suggested, because Kim Jong Il is now a man of reason, because he now can be trusted," asked Ileana Ros-Lehtinen.

Lawmakers skeptical about China's commitment to pressuring Pyongyang cited a report, due to be released Thursday, by the U.S. China Economic Review Commission.

Republican Congressman Dana Rohrabacher:

"[A report] which will indicate that there is ample evidence that China has played a significant negative role when it comes to proliferation of nuclear weapons, especially those dealing with North Korea," he said.

A draft released two weeks ago said while Beijing used some of its influence to encourage North Korea's participation in the six-party talks, it refused to use its leverage effectively regarding Pyongyang's nuclear and missile development activities and eventual nuclear test.

The report also says China's government and industries have continued to provide missile development assistance to Iran, adding that Beijing failed to meet the "threshold test of international responsibility in the area of non-proliferation" where Iran and North Korea are concerned.

Undersecretary Burns says China has communicated its outright opposition to a nuclear-armed North Korea and favors full dismantling of Pyongyang's nuclear industry and weapons complex, adding he is unaware of any Chinese aid to Pyongyang's nuclear program.

He had this exchange with Democratic Congressman William Delahunt:

BURNS: "That is how I understand Chinese policy, that is how they have expressed it to me, and I am not aware personally of any effort by the Chinese government to assist the North Korean nuclear program."

DELAHUNT: "Because that would seem, Ambassador, that would just seem illogical to me, from the perspective of the national security interests of the Chinese, to have a program let alone participate in helping the development of a nuclear weapons program."

Burns' comments tracked closely with statements by the chief U.S. negotiator, Christopher Hill, to media in Hanoi, where the North Korea issue may overshadow economic issues at the APEC summit attended by President Bush.

In a related development, an American nuclear scientist who recently met with North Korean nuclear scientists in North Korea says he believes Pyongyang has enough nuclear fuel for as many as nine weapons.

Siegfried Hecker told a Washington seminar that he believes Pyongyang's nuclear test was at least partially successful, although he said he did not learn any technical specifics from the test. He added that he believes North Korea is still a long way from having a weapon that could be delivered by a missile.