A North Korean envoy said multinational talks on Pyongyang's nuclear programme had made no progress, as delegates ended their eighth day of negotiation.
It was Kim Kye-gwan's first public comment during the talks
"The situation is bad," said Kim Kye-gwan, but added: "We will do our best to reach an agreement."
North Korea wants security guarantees and aid before it will scrap its programme, a condition the US rejects.
The talks, already at record length, are expected to continue into Wednesday.
In the first comment from the North Korean side since this round of talks began in Beijing, Mr Kim told reporters: "The talks lasted for long hours but produced no progress... There are some differences and confrontations over several issues."
Earlier, US envoy Christopher Hill also said there still remained "a lot of differences".
The six nations - the two Koreas, the US, China, Russia and Japan - are currently locked in deadlock over a new draft document written by China.
"We felt the second draft was actually better than the first draft. It clearly reflected the comments of all the parties," Mr Hill said.
But he added: "I need to be very clear that there are a lot of differences between the North Korean side on one hand and everyone else on the other hand."
Chief Japanese negotiator Kenichiro Sasae said the talks "have come close to the moment of truth", adding that it was up to North Korea to help make a breakthrough.
Japanese Foreign Minister Nobutaka Machimura said one of the sticking points was North Korea's denial that it harboured a second, secret nuclear programme, in addition to the plutonium one it has admitted to.
"North Korea still does not acknowledge that it has a uranium enrichment programme," Mr Machimura said from Tokyo.
"The work on the wording of a joint statement is not going smoothly."
North Korea wants security guarantees and aid before it will scrap its nuclear programme. But the US wants North Korea to abandon its nuclear ambitions before any concessions are made.
Oct 2002: US says North Korea is enriching uranium in violation of agreements
Dec 2002: North Korea removes UN seals from Yongbyon nuclear reactor, expels inspectors
Feb 2003: IAEA refers North Korea to UN Security Council
Aug 2003: First round of six-nation talks begins in Beijing
Feb 2005: Pyongyang says it has built nuclear weapons for self-defence
North Korea also wants sanctions against it lifted, and what it sees as a US nuclear threat removed.
It says it will return to the nuclear Non-Proliferation Treaty (NPT) and re-admit international weapons inspectors if the crisis is resolved.
Heated exchanges were reported during the last few days about how the sequence of disarmament should proceed.
The crisis first erupted in 2002 when the United States accused North Korea of pursuing nuclear arms.
The stand-off deepened when Pyongyang withdrew from the NPT and announced earlier this year that it had nuclear weapons.