"There was no talk of a specific date," she said. Asked if the Kim-Trump talks would be held before the US mid-term elections in early November, she said all possibilities remain open.

On her proposal for the US to hold off its demand for the list of the North's nuclear weapons, the minister said the Trump administration seems to "be making preparations with lots of flexibility."

It was Pompeo's fourth visit to Pyongyang in less than a year.

Both Pyongyang and Washington issued relatively positive messages on his latest trip.

A US official traveling with him described it as having gone better than the previous one in July, after which the North accused him of making "gangster-like" demands.

This time, the North's leader was satisfied with the "productive and wonderful" talks with Pompeo on denuclearization and other issues of mutual concern, according to Pyongyang's state news agency, the Korean Central News Agency.

Trump earlier posted on Twitter, saying that the secretary had a good meeting with Kim there and he's looking forward to seeing the North's leader again in the near future.

In a separate statement, the State Department said the two sides "refined options for the location and date of that next summit."

It added that their working-level teams will soon have follow-up talks.

The negotiations are expected to be led by Stephen Biegun, Washington's special representative for Pyongyang, and Choe Sun-hui, the North's vice foreign minister.

"In addition, Chairman Kim invited inspectors to visit the Punggye Ri (Punggye-ri) nuclear test site to confirm that it has been irreversibly dismantled," the department's spokesperson Heather Nauert said.

It represents Pyongyang's new card meant to convince US officials amid skepticism about its disarmament commitment.

In May, the North's held a ceremony to blow up the underground tunnels of its main nuclear test site in the northeastern mountainous region. It allowed only some foreign reporters to cover the event without the presence of outside experts.

Pompeo plans to fly to visit Beijing, the last leg of his Asia swing, later Monday.

Choe, the North's vice foreign minister, is traveling to Moscow for consultations with senior Russian and Chinese officials.

She is scheduled to attend a trilateral session to be joined by her counterparts on Tuesday, the Russian government announced. (Yonhap)