The chief US negotiator at the international meeting on North Korea's nuclear programme has said there was no progress on the first day of talks.
Christopher Hill has warned that US patience is wearing thin
Christopher Hill gave his assessment at the start of the second day of the six-nation talks in Beijing.
On Monday, North Korea said it would not consider halting its nuclear deterrent unless UN sanctions and US financial restrictions were lifted.
Mr Hill responded by warning that Washington's patience was running out.
"I think I would be hard-pressed to say any progress was made. Certainly there was nothing I heard in the plenary [meeting] to fill me up with a sense of holiday spirit," Mr Hill said.
The North's conditions were part of a tough opening statement as talks resumed with the US, China, Japan, Russia and South Korea after a one-year suspension.
The North warned it would increase its nuclear deterrent if its demands were not met.
The UN Security Council authorised sanctions against North Korea following the explosion of an atomic device on 9 October.
Washington imposed financial restrictions last year after it found Pyongyang had engaged in alleged money-laundering and counterfeiting US dollars.
Mr Hill, the US assistant secretary of state, said the impoverished state was not making a serious pitch and had much to lose if the talks failed.
"They should come to it in a mood of trying to reach a deal. North Korea needs schools, health stations, roads, airports. They need a lot of things.
"They need food, electricity. They don't need nuclear weapons," he said, suggesting the North may alter its demands in coming days, when negotiators break into smaller meetings.
North Korean envoy Kim Kye-gwan said on Monday that Pyongyang was unconcerned that other countries did not accept its newly demonstrated nuclear status.
The North says it should be treated on equal footing with the US and that talks should now be about arms reduction.
Kim Kye-gwan (right) has brought a list of demands from Pyongyang
The statement repeated a demand for a nuclear reactor to generate energy.
North Korea walked out of the last round of talks in November 2005 in protest at the US restrictions - imposed on a Macau-based bank linked to alleged money-laundering.
Two months earlier, in September 2005, Pyongyang had agreed to abandon its nuclear programme in return for US security guarantees and aid in a deal that was hailed as historic.
However, Washington say it has no intention of accepting North Korea as a nuclear power.
Japanese officials said late on Monday that it found North Korea's position unacceptable and that Japan shared the view of the United States and South Korea.
Observers say there will be relief the talks are resuming but scepticism about the chance of a major breakthrough.