Secretary of State Mike Pompeo was ensconced in an elegant Pyongyang guest house for a second day of talks with North Korean leader Kim Jong Un's right-hand man Kim Yong Chol.

It was not clear if Pompeo would be granted an audience with the Northern leader himself as he tries to develop a detailed road-map towards the "complete denuclearisation" of the Korean peninsula, as agreed by Kim and US President Donald Trump last month.

But talks were expected to continue at a large guest villa in an official compound in Pyongyang, a short distance from the imposing mausoleum where North Korea's former helmsmen, Kim's grandfather and father, Kim Il Sung and Kim Jong Il lie in state.

Pompeo, who is on his third visit to Pyongyang, began his diplomatic outreach to North Korea when he was still Trump's CIA director and remained the pointman on negotiations after the process became public and he became secretary of state.

Opening the talks after the US envoy arrived on Friday, his opposite number Kim Jong Chol joked to Pompeo that he must be getting used to the city by now.

"The more we meet, the deeper our friendship will be, I hope," he said, adding: "Today's meeting is really meaningful meeting."

Pompeo replied: "Yes, I agree. I look forward to it and I count on it being very productive."

In comparison to past international nuclear disarmament negotiations, and indeed to most major power diplomacy, the discussions between Washington and North Korea on thawing ties and dismantling the North's arsenal appear to be proceeding in reverse.

Last month, Kim and Trump met in Singapore and signed an historic joint statement committing Pyongyang to "work towards complete denuclearisation of the Korean Peninsula" in exchange for US "security guarantees" and lasting peace in the decades-old stand-off.

- Crisis over? -

But rather than the two leaders crowning years of detailed negotiation with their one-on-one meeting, the short statement marked instead the start of a diplomatic long slog and Trump earned the scorn of Korea watchers and non-proliferation experts when he declared the crisis over.

The task of establishing the disarmament programme now falls to Pompeo, who is seeking a formal declaration by the North of the size of its nuclear programme as well as an eventual timetable for it to be stood down under international verification and inspection.

Many experts doubt Kim's sincerity -- a nuclear deterrent to the US military forces massed in South Korea has long been a strategic goal of his isolated, autocratic regime -- and few expect this to be a quick process, even if Washington wants results within a year.

"On this trip I'm seeking to fill in some details on those commitments and continue the momentum toward implementation of what the two leaders promised each other and the world," Pompeo told reporters as he headed to Pyongyang. "I expect that the DPRK (North Korea) is ready to do the same."

Pompeo, accompanied by senior State Department and CIA officials, held almost three hours of talks on Friday evening.

They were due to talk again all day Saturday before Pompeo heads to Tokyo to brief Washington's Japanese and South Korean allies.

Shortly after arriving in Pyongyang, Pompeo laughed off reports in the South Korean press that he was carrying an Elton John CD.

The South Korean newspaper Chosun Ilbo, citing unnamed Washington sources, said the "Rocket Man" CD was a gift for Kim Jong Un -- a reference to Trump's former habit of insultingly referring to the North Korean as "Little Rocket Man".