North Korea has denied US President Donald Trump's claim that the country demanded total sanctions relief during a failed summit in Hanoi.
The North's Foreign Minister Ri Yong-ho was speaking after talks between US President Donald Trump and North Korean leader Kim Jong-un ended without agreement.
He said they asked only for partial sanctions relief in exchange for disabling its main nuclear complex.
The US insists this is not the case.
After their talks broke down, Mr Trump said Mr Kim had offered to dismantle all of the Yongbyon complex, the research and production facility at the heart of North Korea's nuclear programme, a significant proposal.
But in return Mr Kim wanted all sanctions lifted, something the US was not prepared to offer, Mr Trump added.
North Korea: We asked for 'partial relief'
At a late-night news conference after Thursday's summit, Mr Ri said his country had made "realistic" proposals, including the complete decommissioning of Yongbyon, under the watch of US observers.
"This proposal was the biggest denuclearisation measure we could take at the present stage when taking into consideration the current level of confidence between the DPRK [North Korea] and the United States."
In return, Mr Ri said, the North had wanted only partial lifting of sanctions "that hamper the civilian economy and the livelihood of our people".
He told reporters Pyongyang had also offered to permanently halt nuclear and long-range rocket testing. He added that it might be hard to see an opportunity such as the Hanoi summit again.
"Our principal stand will remain invariable and our proposals will never change, even if the United States proposes negotiations again in the future."
Why did the summit fail?
By Jonathan Head, BBC News, Hanoi
President Trump was more philosophical than defensive over the summit failure, suggesting he half-expected it to happen. And the North Korean reaction so far, from Foreign Minister Ri Yong-ho, has been measured. This was, to the participants, less a shock than a disappointment.
US officials say the North Koreans would not define exactly what they meant by the Yongbyon complex; the US is believed to have asked to include other hitherto unpublished nuclear facilities. Nor could the two sides agree on what denuclearisation means. US officials say they were being offered an end to testing, and partial destruction of facilities but that leaves North Korea's existing nuclear arsenal intact.
Secretary of State Mike Pompeo said they had cleared away what he called "a lot of the brush" in the weeks of pre-summit talks, but there remained gaps between the two sides they had hoped to close when the two leaders were in the same room. That didn't happen.
President Trump has shown Chairman Kim that, notwithstanding his hunger for a deal, he is prepared to walk away. But he has also shown the world that his famous deal-making skills are no match for a diplomatic problem as thorny as North Korea.
US: They asked for 'full relief'
At a news conference after the summit, Mr Trump also said: "It was all about the sanctions. They wanted the sanctions lifted in their entirety and we couldn't do that. Sometimes you have to walk and this was one of those times."
Following Mr Ri's comments, US Secretary of State Mike Pompeo, who took part in the summit in Hanoi, reaffirmed that North Korea had "basically asked for full sanctions relief".
"They were pretty expansive with respect to what they're prepared to do at Yongbyon but there was still not complete clarity with respect to full scope of what it is they were prepared to offer," he told reporters.
The US was "anxious to get back to the table" to continue the talks, he added.
On the flight back to the US, Mr Trump reassured Japanese Prime Minister Shinzo Abe and South Korean President Moon Jae-in that talks with the North would continue, White House press secretary Sarah Sanders said.
Later she wrote on Twitter: "President Obama refused to walk away from a bad deal with Iran. President [Trump] refuses to make the same mistake with Iran, North Korea, or anybody else. President Trump will always put the safety of the American people above politics."
The main sticking points
Another contentious point included the network of facilities that extend beyond Yongbyon. Last month, Stephen Biegun, the US state department special representative for North Korea, said Pyongyang had committed in pre-summit talks to destroy all the nation's plutonium - and uranium-enrichment facilities, dependent on unspecified US measures in return.
Those unspecified US measures appear to have been complete sanctions relief, which Mr Trump would not offer. The US president also suggested in his news conference that Mr Kim had offered only the destruction of Yongbyon and not North Korea's entire nuclear apparatus.
Yongbyon is North Korea's only known source of plutonium but the country is believed to have at least two other facilities where uranium is enriched.
Mr Trump said when he raised the issue of a second enrichment facility apart from Yongbyon, the North Korean delegation was "surprised" by what the US knew.