Ri Yong Ho is expected to meet Swedish counterpart Margot Wallstrom "in the near future", diplomatic sources told the daily Dagens Nyheter, without specifying what they would discuss.

Contacted by AFP, the Swedish foreign ministry refused to comment.

The report comes after Trump floored his own advisors when he agreed to accept an offer to meet nuclear-armed dictator Kim before the end of May.

One issue to be resolved is where those talks will take place.

Sweden's embassy in Pyongyang represents US, Canadian and Australian diplomatic interests in North Korea and plays a key role in liaising diplomatic talks.

Trump thanked Swedish Prime Minister Stefan Lofven for Stockholm's efforts to negotiate the release of US student Otto Warmbier, who was arrested for stealing propaganda material during a 2016 trip to Pyongyang and later died when he returned to his country.

Washington has long insisted that it will not allow Pyongyang to continue building and testing a nuclear arsenal. Kim's regime boasts it is now capable of delivering thermonuclear warheads to US cities.