Six nations were on Tuesday expected to announce a deal to end North Korea's nuclear weapons programme after Pyongyang reportedly agreed to disable key nuclear facilities within two months.
"The chief negotiators finalised the wording of the joint statement," South Korea's Yonhap news agency quoted a South Korean diplomat as saying.
The negotiators worked into the early hours of Tuesday to secure an agreement, making "a lot of progress", US envoy Christopher Hill said.
The six chief negotiators met again on Tuesday morning to finalise the wording of the agreement between North Korea, the US, China, South Korea, Japan and Russia, host nation China said.
Yonhap quoted sources as saying the other five nations agreed to provide Pyongyang with energy equivalent to one million tonnes of heavy fuel oil each year if it "disables" its nuclear facilities within two months.
"The planned energy assistance will be composed of 500,000 tonnes of heavy fuel oil and some other electricity," a source said on condition of anonymity.
Details of the energy aid would be discussed soon at a six-nation "working group", and the six nations also planned to hold a meeting of foreign ministers in the near future, it said.
The agreement drafted by China reportedly proposes setting up five working groups to oversee the process of denuclearisation in North Korea.
Other working groups include one group on the steps to be taken by North Korea to abandon its nuclear programme and one to normalise diplomatic relations between North Korea and Japan, Japan's Kyodo news agency said earlier.
North Korea would reportedly agree to inspections by the International Atomic Energy Agency, the UN's nuclear watchdog, the Japanese media said.
A pro-Pyongyang newspaper based in Japan claimed that the US had promised to lift financial sanctions imposed on North Korea within 30 days in return for it taking the first steps toward dismantling its nuclear weapons programmes within 60 days.
The negotiations were the second round since North Korea detonated its first atomic bomb on October 9 - an event that prompted international sanctions against the Stalinist state.
During six-nation talks in September 2005, North Korea agreed in principle to give up its nuclear weapons programme in return for security guarantees from the US and economic aid, but since then, no progress has been made in implementing that agreement.