North Korea said on Friday that US proposals at the six-way negotiations on Pyongyang's nuclear ambitions had been "beyond tolerance" and showed Washington’s desire to disarm the communist state and then invade.
The official KCNA news agency quoted Kim Yong-il, the North's delegate at the Beijing talks that ended on Friday, as saying Pyongyang had hoped to express the will to scrap its nuclear programme "in return for the US manifestation of its will to make a policy switchover at least".
But this expectation had been betrayed, he said.
In a tried and tested proposal certain to be rejected by the United States, KCNA said that Pyongyang had suggested dismantling its nuclear programme in return for a non-aggression treaty with the United States.
US Assistant Secretary of State James Kelly kept his cards close to his chest but gave no indication of a shift and diplomats said the discussions were an opportunity for all sides to lay out their positions and not a forum for negotiation.
The only result came when host China said all six countries - the two Koreas, Japan, Russia, the United States and China - were in agreement to work towards a Korean peninsula free of nuclear arms and would meet again within two months.
Underscoring the urgency of the standoff, the head of the International Atomic Energy Agency (IAEA) Muhammad ElBaradei said North Korea had been guilty of nuclear "blackmail".
"I don't think they can be trusted," the chief of the UN’s nuclear watchdog told the BBC. "However, we would like to work with them and bring them back to the Non-Proliferation Treaty (NPT)."
North Korea posed the world's biggest nuclear threat, he said.
Host Beijing, keen to be midwife to some form of result from the highest-level talks since the nuclear standoff erupted 10 months ago, said all sides "explained their principled stands and proposals on resolving the Korean nuclear issue".
"If the US continues to demand we drop the nuclear programme first and ignores our proposals, we have no choice but to beef up our nuclear deterrent power"
North Korean junior deputy foreign minister
"They also 'frankly' exchanged views," the Xinhua news agency said in a brief dispatch.
The crisis may require many more rounds of talks because the United States, which says Pyongyang may already have one or two nuclear weapons, is looking for a commitment that North Korea will scrap its programme before making any concessions.
Isolated and reclusive North Korea wants security guarantees before dismantling.
N Korea repeats terms
Twinning sweeteners with threats, the North's junior deputy foreign minister, Kim Yong-il, raised the rhetoric on the second day by speaking about carrying out a test and saying North Korea could declare itself a nuclear power, said US officials.
Despite the wide gulf, the White House played down Pyongyang's comments on arms tests and sought to stress North Korea's isolation by lauding the level of cooperation at the talks, which have so far proved a diplomatic coup for host China.
North Korea stood firm, reiterating that it would not build nuclear arms only in return for a non-aggression treaty with the United States.
"We can give up the nuclear programme if the United States drops its hostile policy towards North Korea," Kim Yong-il said in a speech released by the North's official KCNA news agency.
North Korea wants a package including a non-aggression treaty and diplomatic relations with the United States and Japan, KCNA said.
"In return, the DPRK will not manufacture nuclear weapons and allow in inspection, realise the ultimate dismantlement of nuclear facilities and stop the export and experiment of missiles," it said.
Even agreement on more talks can be seen as a success after the three days of talks. Negotiations involving China, the United States and North Korea broke up amid anger last April.