US Secretary of State Mike Pompeo has described his negotiations with officials in North Korea on dismantling Pyongyang's nuclear arsenal as "very productive".
"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," Pompeo told reporters on Saturday as he was making departure for Tokyo after spending two days in Pyongyang.
Pompeo spoke after emerging from more than eight hours of talks over two days with North Korean leader Kim Jong-un's right-hand man Kim Yong-chol in a Pyongyang diplomatic compound.
Last month, at a historic summit with US President Donald Trump, Kim agreed to "work towards complete denuclearization of the Korean Peninsula" in return for security guarantees and an end to a dangerous stand-off with US forces.
Since then, the onus has been upon Pompeo to follow up on the issue as the point-man on negotiations.
Pompeo’s visit to Pyongyang on Friday was his third visit and first overnight stay, and he left en route to brief his Japanese and South Korean counterparts in an upbeat frame of mind.
"We talked about what the North Koreans are continuing to do and how it's the case that we can get our arms around achieving what Chairman Kim and President Trump both agreed to, which is the complete denuclearization of North Korea," he said.
"No-one walked away from that, they're still equally committed. Chairman Kim is still committed, I had a chance to speak to President Trump this morning.
"I know my counterpart spoke with Chairman Kim during the course of our negotiations as well. We had productive, good-faith negotiations."
Pompeo said that officials from both sides would meet on July 12 as a working group to discuss the repatriation of the remains of some US soldiers killed during the 1950-1953 Korean War.
The top US diplomat added that some progress had been made towards agreeing "the modalities" of North Korea's destruction of a missile facility.
Some analysts, however, do not believe Pyongyang intends to give up its nuclear or ballistic missile weapons program easily any time soon.
Pyongyang knows very well that accepting to dismantle its nuclear arsenal could ultimately lead to its destruction as was the case in Libya.
Analysts believe Pompeo’s short statement on Saturday regarding dismantling Pyongyang's nuclear arsenal marks the onset of a diplomatic long slog. They believe Pompeo, who is pursuing a formal declaration by the North of the size of its nuclear program as well as an eventual timetable for it to be ended under international verification and inspection, will need years of detailed negotiation for this.