Negotiators have completed the second of three days of talks on North Korea's nuclear plans.
Talks are focused on programmes at the Yongbyon nuclear site
South Korea has proposed that the North end its nuclear programme in return for compensation.
A diplomat told Reuters there were "no major problems" during Thursday's talks but no other details have emerged.
The latest round of the six-nation summit in Beijing comes after an hour-long meeting between the US and the North on the sidelines of the talks.
Washington has consistently rejected Pyongyang's calls for direct negotiations but there is no indication that the two sides have narrowed their differences.
China, US, Russia, Japan, North and South Korea taking part
Set to last until Friday
Parties sit at hexagonal table, US next to N Korea
Nevertheless, the BBC's Charles Scanlon in Beijing says the very fact that a bilateral meeting took place on the sidelines of Wednesday's talks is a sign of growing flexibility from the US.
In a statement at the opening of talks on Wednesday, US envoy James Kelly repeated a call for North Korea to completely, irreversibly and verifiably dismantle its nuclear weapons programmes.
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North Korea again denied the existence of the uranium programme - it only offered to freeze its better-known plutonium-production plant in return for economic aid.
But our correspondent says the head of the North Korean team, Kim Kye-gwan, was unusually upbeat in his opening remarks, saying Pyongyang would be flexible.
"The resumption of six-party talks... is a reflection of the shared will of all the participants to peacefully resolve the nuclear issue," Mr Kim said.
North Korea has been demanding economic help and diplomatic recognition in return for a freeze of its plutonium plant at Yongbyon.
South Korea's proposal to end the impasse is believed to include three phases:
Phase 1: North Korea states its readiness to dismantle its nuclear programmes. In return, the US states its readiness to provide security guarantees for North Korea
Phase 2: North Korea dismantles its nuclear programmes; once verified, this earns North Korea energy aid and other rewards
Phase 3: The resolution of all other issues and the improvement of relations
It is unclear whether the US, or any other party, has endorsed the South's offer.
The nuclear crisis erupted in October 2002, when the US said North Korea admitted having an enriched uranium programme, in violation of a 1994 agreement.