"They had a meeting. We will not disclose what they talked about," Lofven's spokesman Jonatan Holst told AFP.

Ri Yong Ho arrived in the Swedish capital on Thursday evening with Choe Kang Il, deputy director general of the foreign ministry's North America section.

Ri held talks late Thursday with his Swedish counterpart Margot Wallstrom, discussions which according to Swedish officials were to focus on the denuclearisation of the Korean peninsula and a possible Trump-Kim summit.

The talks were to continue on Friday.

"Right now, dialogue is needed and we are happy to have this meeting. But we're not naive, we don't think we can solve the world's problems. It is up the parties to decide how to move forward," Wallstrom told Swedish media in parliament on Friday.

"If we can use our contacts in the best way, we will do so," she said, noting the situation on the Korean peninsula was "of interest to us all" in terms of security.

Some Swedish and foreign media have said that Ri -- who was stationed at North Korea's embassy in Stockholm in 1985-1988 -- will stay in the Scandinavian country until Sunday for other talks, though Swedish officials would not confirm those reports.

"We can't rule out the possibility of a contact between the North and the US" during Ri's visit, a Beijing source told South Korea's Yonhap agency.

Swedish public broadcaster SVT meanwhile said the Stockholm International Peace Research Institute (SIPRI) was involved in the talks, though SIPRI did not return AFP's calls for a comment.

Sweden has longstanding ties with North Korea. Its diplomatic mission in Pyongyang, which opened in 1975, was the first Western embassy established in the country.

The embassy also represents US, Canadian and Australian diplomatic interests in North Korea, with Sweden playing a key role in liaising diplomatic talks.

- 'Ready to play a role' -

International media have speculated that Sweden could either help set up a proposed summit or be a potential location if a tete-a-tete were to be confirmed.

Sweden's foreign ministry has refused to comment on that possibility, saying only that the talks would "focus on Sweden's consular responsibilities as a protecting power for the United States, Canada and Australia."

"They will also address the security situation on the Korean peninsula, which is high on the (UN) Security Council agenda," a ministry statement said. Sweden is currently a non-permanent member of the Security Council.

"The aim of the visit is to contribute to the effective implementation of the resolutions" voted by the Security Council against Pyongyang over its nuclear programme, as well as those calling "for intensified diplomatic efforts to find a peaceful solution to the conflict".

After months of tension and warmongering over Pyongyang's nuclear programme, Trump has agreed to a summit proposal relayed by South Korean envoys who met Kim Jong Un in Pyongyang.

But no specific time or venue has been set and North Korea has yet to confirm it even made the offer to meet.

Lofven on Thursday said Sweden was "ready to" play a role if asked.