Negotiators from six nations have agreed on steps to verify North Korea's nuclear disarmament.
Saturday's agreement opens the final phase in efforts to rid the country of nuclear weapons.
The pact was reached after three days of talks.
North Korea is now expected to finish disabling its biggest nuclear facility by the end of October while the United States, China, Russia, Japan and South Korea would complete promised deliveries of fuel oil and other economic aid.
Beyond that, the envoys agreed on verification regime to inspect North Korean nuclear facilities, review its documents and interview its technical experts.
Qin Gang, a Chinese foreign ministry spokesman, said "some positive progress had been made," with negotiators reaching a "principled consensus" on verification but that specific details still needed to be worked out.
Separate working group meetings focused on the more technical aspects of denuclearisation of the Korean peninsula as well as economic and energy cooperation with North Korea, he said.
"We're striving for it to end. Each delegation is working toward that goal, not only to end ... but to end with results," Qin said.
Christopher Hill, US nuclear envoy said working out the verification details could take several days.
"When you start talking on the verification protocol you very quickly go into great detail so it does take a while," Hill said.
He said he expects the verification process could take weeks or even months.
"We're not asking for anything unusual. We're asking for things that are done all over the world. We want a basically standard kind of package on how you verify this type of nuclear program," he said.
The six-nation talks which involve China as host, the two Koreas, the United States, Japan and Russia - began in 2003 with the aim of persuading North Korea to abandon its nuclear programmes.
However they had not been held since October, as the other parties involved waited for North Korea to give an accurate account of the nuclear programmes it had spent decades developing.
The declaration was a key part of the six-nation disarmament accord reached last year, under which the North agreed to abandon its nuclear programmes in exchange for an array of diplomatic incentives and economic aid.
North Korea has complained that it has not been given what was promised in fuel aid under a February 2007 disarmament deal.
Japan has opted out of contributing, citing a lack of progress by North Korea in resolving the issue of its abductions of Japanese citizens in the 1970s and 1980s.
North Korea has complained that countries involved in the talks have supplied only 40 percent of promised energy shipments.
In response to North Korea's nuclear declaration last month, the United States announced it would remove the country from a list of state sponsors of terrorism and relax some economic sanctions against it.
The third and final phase of the disarmament deal calls for the North to permanently dismantle its atomic plants and hand over all nuclear material and weaponry.
In return, it would get more energy aid, restored diplomatic ties with the United States and Japan, and a formal peace treaty to officially end the 1950-1953 Korean War.