"What we hope to do in this round is to implement a first tranche of measures, which will be the beginning of the full implementation of the September (2005) agreement leading to full denuclearization of the Korean peninsula," Assistant Secretary of State Christopher Hill told reporters.

He said that the move "will be a substantial start" to making the Korean peninsula nuclear weapons free and added that "there is a basis for making progress" at the talks in the Chinese capital beginning February 8.

Hill declined to elaborate on the measures but some experts familiar with the talks said the steps could be linked to a freeze by Pyongyang on its nuclear activities at the key Yongbyon reactor in return for some benefits.

The Yongbyon complex produces spent fuel that can be "reprocessed" to yield plutonium for a nuclear weapon.

The step-by-step process for North Korea to abandon its atomic weapons program is seen as a rollback by the administration of President George W. Bush's demand for a "complete, verifiable, and irreversible" dismantlement of Pyongyang's nuclear arsenal when multilateral talks were launched in 2003.

Apparently referring to Pyongyang's breach of an earlier agreement to freeze in nuclear activities, Hill said North Korea had been told explicitly that it could not shed its nuclear pariah status unless it completely disbanded its atomic weapons network.

"We have made it clear to the North Koreans that they should not be in this for the first tranche because we have a situation where a country has produced plutonium -- depending on who you believe -- for nuclear weapons.

"Clear denuclearization is not achieved unless North Korea can get back into the nuclear Non-Proliferation Treaty as a non-nuclear state and they are not going to be able do that until they give up these nuclear weapons and nuclear programs," he explained.

"I think they understand that they have to move beyond the first tranche."

Under the September 2005 deal, reached through an earlier series of talks among the United States, North Korea, China, Russia, Japan and South Korea, Pyongyang agreed to give up its atomic weapons program in exchange for security guarantees, economic aid and improved relations with Washington.

But North Korea walked away from the agreement a month later in protest at the imposition of US financial sanctions against a Macau bank accused of money-laundering for the regime in Pyongyang.

As part of the deal that enticed North Korea back to negotiations last month, Washington agreed to discuss the sanctions imposed on Banco Delta Asia (BDA) in parallel with the resumed denuclearization talks.

The last round of six-party negotiations in December ended in stalemate after North Korea, emboldened by its first-ever test of an atomic bomb in October last year, insisted that the US sanctions and broader UN measures imposed against the North be lifted.

The two sides held two days of "very productive" discussions in Beijing this week on the financial sanctions, US negotiator Daniel Glaser told reporters in the Chinese capital Thursday.

Asian diplomats said the United States was pushing North Korea to pledge in a written statement it would take immediate action towards denuclearization at the Beijing talks next week.

Aside from Yongbyon, Pyongyang is reportedly building a large reactor in Taechon capable of making about 10 nuclear bombs a year.