The talks, which also involve South Korea, China, Japan and Russia, resumed Thursday in Beijing amid hopes for progress toward implementing a September 2005 agreement, in which Pyongyang committed itself to halting its nuclear activities in return for economic and security incentives.
"Right now, bilateral contacts are ongoing and it is not ruled out that they will continue until Tuesday," the source said, adding that an agreement is still possible.
The United States and South Korea rejected Pyongyang's demands that security guarantees, specifically non-aggression by the U.S., be included in a joint statement.
Reports earlier today said North Korea is ready to remove graphite rods from its nuclear reactor in Yongbyon in exchange for greater energy assistance.
North Korea asked for the delivery of power generating facilities to produce 255,000 KW a year in return for stopping its five-megawatt nuclear reactor. Its negotiating partners proposed that the reactor be "disabled" by removing its nuclear fuel.
Pyongyang asked for 1 million metric tons of fuel oil for its heat and electric power plants, while its negotiating partners said they are ready to supply 500,000 tons.
At a meeting in Berlin last month, U.S. Assistant Secretary of State Christopher Hill and North Korean Deputy Foreign Minister Kim Kye Gwan discussed a U.S. freeze of the reclusive regime's Macao bank account over alleged money laundering and counterfeiting. The sanctions prompted the North to withdraw from the six-party talks in 2005.
Pyongyang, which announced its first nuclear weapon test last October, hinted in the run-up to this round of Beijing talks that it may be willing to suspend operations at its Yongbyon nuclear facility, which helped it stage the test, if the U.S. delivers on an earlier promise to build a light-water reactor in North Korea and to provide it with steady fuel oil supplies pending the facility's construction.
China presented a draft plan for North Korea's nuclear disarmament.
The plan proposes closing and sealing North Korean nuclear facilities, including a five-megawatt reactor at the Yongbyon Nuclear Scientific Research Center, 100 kilometers (60 miles) north of Pyongyang, and the provision of alternative energy sources and economic aid to the impoverished North by the other parties to the talks.
The plan also envisions setting up five working groups to oversee denuclearization efforts on the Korean Peninsula, energy supplies to North Korea, cooperation in the security sphere in Northeast Asia, and relations between North Korea and the United States and Japan.
