North Korea's foreign minister has briefly met Sweden's prime minister during a surprise trip to Stockholm that has fuelled speculation about a possible meeting between Donald Trump and Kim Jong Un.
The US president has agreed to meet Mr Kim by May.
So far, North Korea has yet to publicly comment on what it hopes to gain from the talks.
Sweden has been rumoured as a possible site for the summit between the two men, although a truce village on the South Korean side of the Demilitarised Zone between the Koreas is seen as more likely.
North Korean foreign minister Ri Yong Ho landed in Stockholm on a flight from Beijing late on Thursday and held talks with Swedish counterpart Margot Wallstrom before returning to the North Korean embassy.
He is expected to meet her again on Friday.
Before doing so, Mr Ri held what was thought to be a courtesy call with prime minister Stefan Lofven at government headquarters.
Details about their talks were not revealed as Mr Ri's visit to Stockholm, where he once served as a diplomat at the North Korean embassy, is shrouded in secrecy.
The Swedish foreign ministry said talks "will focus on Sweden's consular responsibilities as a protecting power for the United States, Canada and Australia", but will also address the security situation on the Korean peninsula".
It added that a statement summarising the talks will be made available after Mr Ri's talks with Ms Wallstrom.
"It is evident that the whole world is following the situation on the Korean peninsula. It is important for everyone's security," she said in her first comments since Mr Ri landed in Stockholm.
"But we are not naive in believing we can solve the world's problems. It is up to the parties to decide which way we are going."
Sweden has had diplomatic relations with North Korea since 1973 and is one of the few Western countries with an embassy in Pyongyang. It provides consular services for the US in North Korea.
The trip by Mr Ri is being closely watched because a huge amount of preparation needs to be done in relatively little time before a theoretical Trump-Kim summit - if it is to happen by May.
Senior South Korean officials who travelled to North Korean capital Pyongyang earlier this month and met Mr Kim say he is willing to discuss the North's nuclear weapons programme.
It could suggest a potential breakthrough, or a fallback to the North's long-standing position that it is willing to get rid of its nuclear weapons if the US guarantees its safety.
In the past, that has meant Washington would have to withdraw all of its troops from South Korea, a condition no US president has been willing to consider.