North Korea has accused the United States of making “gangster-like” demands, contradicting US Secretary of State Mike Pompeo just hours after he insisted the old enemies had made progress on key issues.

During a day and a half of talks in Pyongyang, Mr Pompeo sought to hammer out details on how to dismantle North Korea’s nuclear programs, including a timeline.

North Korea had formerly promised to end its nuclear program but now is sending mixed signals about its actual intentions, US officials said.

As Mr Pompeo departed for a meeting with Japanese foreign minister Taro Kono in Tokyo, he said he had made progress on “almost all of the central issues”, although he cautioned that much work remained to be done.

CIA chief Mike Pompeo tries to put a positive spin on the talks as he leaves Pyongyang for Tokyo. Photo: AP/Andrew Harnik

Hours later, Pyongyang provided a far more negative assessment, saying Washington had violated the spirit of last month’s summit between US President Donald Trump and North Korean leader Kim Jong-un.

“The US side came up only with its unilateral and gangster-like demand for denuclearisation,” a North Korean foreign ministry spokesman said in a statement on Saturday carried by the official KCNA news agency.

He said Pompeo’s delegation insisted on unilateral complete, verifiable and irreversible denuclearisation, known as CVID.

“The high-level talks this time brought us in a dangerous situation where we may be shaken in our unshakable will for denuclearisation, rather than consolidating trust between the DPRK and the US,” the North Korean statement said.

The contrasting comments raised fears North Korea is once again using bait-and-switch tactics – promising one thing only to reverse its position without warning or explanation.

Under a “deal” cut with former President Bill Clinton, North Korea pledged to scrap its nuclear program in return for massive aid. That promised proved shortlived when US intelligence resources confirmed  atomic weapons development was ongoing.

North Korea’s renewed defiance coincided with the annual nationalistic fervour as the country honoured its founding family. Photo: AP/Andrew Harnik

Trump and Kim pledged at their June 12 summit meeting in Singapore to move towards denuclearisation of the Korean peninsula.

Trump has declared on Twitter that North Korea no longer poses a nuclear threat.

But Kim has yet to provide details of how or when North Korea might dismantle a weapons program that Trump has vowed will not be allowed to threaten the US.

On Saturday, Pompeo said he spent “a good deal of time” in the latest talks discussing a denuclearisation timeline and the declaration of the North’s nuclear and missile facilities.

“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.

Some US experts on North Korea said the ongoing disputes show the risk of Washington granting premature concessions to Pyongyang. Many were surprised when Trump agreed at the summit in Singapore to end joint military exercises with South Korea.

“The North Koreans are in the game to get, not to give,” said Daniel Russel, the top US diplomat for East Asia until last year.

“They have gotten the US to back off military exercises, back off using ‘CVID’, back off the ‘Libya model’ of rapid denuclearisation, back off on human rights, and to look the other way while China relaxes sanctions implementation.

“So why wouldn’t Kim Jong-un dig in his heels with Pompeo and press his advantage?”

State Department spokeswoman Heather Nauert said Pompeo had been “very firm” on three basic goals: complete denuclearisation of North Korea, security assurances and repatriation of remains of Americans killed in the 1950-53 Korean War.

-AAP