Christopher Hill, the leading US envoy in Beijing, said that North Korea was at odds with the other five countries over a single paragraph in the draft agreement, but South Korea and Japan hold out little hope of a deal.
"I think it's time to wrap this up and get moving and I hope the other participants will share this view," Hill said on Sunday.
"... We've made a lot of progress. It's progress that's consolidated. We've got this one issue - we ought to try to wrap this issue up."Remaining issue
"North Korea is making a fool out of Bush and the Neocons. It is amazing that the more stubborn the North Koreans the more, they are rewarded by so many goodies"
B Humble, UK
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Hill refused to set out what the remaining issue was, but said he believed it was one to be discussed by experts in a working group.
Japan's Kyodo news agency reported that North Korea had demanded energy aid equivalent to more than two million tonnes of fuel oil a year in exchange for the initial steps towards abandoning its nuclear weapons capability.
Chun Yung-woo, the South Korean envoy, said the sticking point was not over how much energy to give the North but how any energy and economic aid is "tied to the scope and speed of the actions of denuclearisation" to be taken by the North.
"It's a bit unreasonable to expect there'll be a breakthrough today," he said.
Other diplomats have said the row is over the incentives Pyongyang would receive in return for shutting down its Yongbyon nuclear plant, which makes plutonium which could be used in nuclear weapons.Nuclear disarmament
In September 2005, the US, China, Russia, South Korea, Japan and North Korea agreed a joint statement which set out out the nuclear disarmament steps that Pyongyang needed to take to secure fuel and economic aid, as well as political acceptance from the US.
But that deal was ignored by North Korea after it was accused by Washington in late 2005 of counterfeiting US currency and other illicit business.
The ensuing crackdown on a bank in Macau enraged Pyongyang, which stayed away from the six-party talks until international condemnation after the nuclear test drew it back in December.
Hill told reporters that the negotiators were still hopeful that a joint statement could be agreed and said it was worth staying in China to try to clinch the deal.
Asked when the talks would finish, he said: "I don't want to celebrate Chinese New Year in Beijing." The holiday begins on February 18.