North Korea has branded the US attitude at the latest talks over its nuclear programme "regrettable".

The statement, by an unnamed foreign ministry official, contradicted the version of events given by US Secretary of State Mike Pompeo just hours before.

Mr Pompeo had said progress was made during the two days he was in Pyongyang to discuss the issue.

It was the first time he had visited North Korea since the Donald Trump-Kim Jong-un summit in Singapore.

The North Korean statement, carried by the official KCNA news agency, said the US had gone against the spirit of the summit by putting unilateral pressure on the country to abandon its nuclear weapons. 

A key aim of Mr Pompeo's two days of talks was to firm up North Korea's commitment to denuclearisation.

He met with Kim Yong-chol, widely seen as North Korean leader Kim Jong-un's right-hand man.

Afterwards, Mr Pompeo gave little away about the talks' content, but he said they had discussed at length a timeline for disarmament, including the destruction of a missile engine testing facility.

"These are complicated issues, but we made progress on almost all of the central issues, some places a great deal of progress, other places there's still more work to be done," he said, shortly before North Korea gave its far more critical take on the meeting.

Kim Jong-un has promised to work towards denuclearisation, but details on how this will be achieved remain thin.

After the Singapore summit, which also saw the US offer "security guarantees" to North Korea and promise to end its military drills with South Korea, Mr Trump claimed that the North no longer posed a nuclear threat.

However, the president has since renewed sanctions on North Korea, while US intelligence officials have said there is evidence North Korea continues to upgrade the infrastructure for its nuclear and missile programmes.

A state department spokesperson said Mr Pompeo had been "very firm" in focusing on denuclearisation, as well as on security assurances and another important US demand - the return of remains of US service personnel from the Korean War.

Kim Yong-chol joked that Mr Pompeo may not have slept well during his overnight stay at a guesthouse in Pyongyang. Mr Pompeo said he "slept just fine".

On Sunday, the US secretary of state will meet the foreign ministers of Japan and South Korea in Tokyo.