(CNN) North Korea's foreign minister is visiting Sweden, the first significant diplomatic move by Pyongyang since US President Donald Trump said a week ago that he'd be willing to meet North Korean leader Kim Jong Un.

Ri was seen by a CNN crew arriving at the Swedish Foreign Ministry Thursday evening.

Sweden, whose embassy represents US interests in the North Korean capital, has been touted as a possible venue for the momentous summit between Kim and Trump, and the visit will fuel speculation that a Stockholm encounter is in the cards.

Talks between Swedish Foreign Minister Margot Wallstrom and her North Korean counterpart, Ri Yong Ho, will "focus on Sweden's consular responsibilities as a protecting power for the United States, Canada and Australia," the Swedish government said, announcing the two-day visit

The security situation on the Korean Peninsula is also on the agenda.

North Korea has made no official comment on the proposed face-to-face meeting since Trump accepted Kim's invitation, which was delivered verbally by a South Korean delegation. But diplomatic sources have signaled enough confidence in South Korea's words and actions that most of the parties are pressing ahead.

As North Korea's top diplomat, Ri is one of the most visible faces of a country shrouded in secrecy.

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He made headlines last year by telling reporters that Kim could order a hydrogen bomb test over the Pacific Ocean in response to insults from Trump. He also said Trump was "mentally deranged" and likened his threats to "a dog barking."

The trip to Sweden comes as Nirj Deva, the chair of a European parliamentary delegation, told reporters that his group has been holding secret meetings with senior members of the North Korean regime over the past three years to try to convince it to return to peace talks.

Speaking Wednesday at a news conference in Strasbourg, the British-based member of the European Parliament said he and his colleagues have been "relentlessly advocating the case for dialogue without preconditions -- preconditions which I knew would abort any successful talks even before they started."

"We met in secret with senior North Koreans on 14 occasions," Deva said. "We understood their concerns and they understood ours."

Why Sweden?

Sweden is one of a handful of places analysts believe could host the meeting, as its Pyongyang embassy is often used as an intermediary for communication between the regime and countries with which it has no diplomatic ties.

The release of Otto Warmbier , the US student who was imprisoned in North Korea, was mediated by Swedish diplomats, for example.

Sweden was one of the first non-communist countries to establish diplomatic relations with North Korea in 1973. It posted diplomats there shortly thereafter, said Jim Hoare, Britain's former charge d'affaires in Pyongyang.

"The Swedes have this long-established presence in North Korea, so since the 1990s, they've particularly looked after US interests," Hoare told CNN. "There is a long record of Sweden interacting with North Korea on behalf of the Americans. There is this tradition, this link."

However, Hoare said he wasn't sure Kim would travel to a European country, where there might be attempts to arrest him.

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Other options

Other possible summit locations include: Switzerland, the neutral nation where Kim went to school; the Joint Security Area in the demilitarized zone that divides North and South Korea; and China, which has diplomatic relations with the United States and North Korea and has hosted Kim's father, the late North Korean leader Kim Jong Il.

"But the North Korean relationship with China is not very good at the moment," Hoare said.

"If they hadn't fallen out with the Malaysians, one might have thought that could have been a place," he added, referring to a diplomatic rift between Kuala Lumpur and Pyongyang over the suspected assassination of Kim's half-brother , Kim Jong Nam, by North Korean agents.

Regardless of where the summit happens, if it happens, Trump would become the first sitting US President to meet with a North Korean leader.

Deva, the European Parliament member, hailed Trump's decision to accept an invitation from Kim as "an unprecedented display of diplomacy."

He said that the talks between Trump and Kim would only be successful if there are no preconditions.

"To me, the case is simple," he told journalists. "What we are witnessing on the Peninsula is a remnant of the Cold War in which a clash between the opposing ideologies of communism and capitalism continue to this day. This is Cold War Mark II."

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Out of the blue

The reclusive regime had made overtures to US leaders in the past, but none took up the offer

The closest contact Pyongyang has had with a US administration came in 2000, when then-President Bill Clinton's Secretary of State, Madeleine Albright, visited the country to lay the groundwork for a mooted meeting between the countries' leaders.

However, as US diplomats worked to set up the presidential visit, it became clear that North Korea and the US were too far apart on the details of a missile pact to justify handing then-leader Kim Jong Il the huge concession of a Clinton visit.

The idea that Trump and Kim Jong Un would sit down together was unthinkable just months ago, when North Korea was regularly testing weapons in its pursuit of developing a missile that could deliver a nuclear warhead to the United States.

The diplomatic wheels started turning rapidly at the beginning of the year, when the two Koreas worked to bring a handful of athletes from the North to compete in the Winter Olympics in South Korea.

Since the end of the Games, Kim has hosted a high-level delegation from Seoul, which delivered the summit offer to Trump.

South Korean President Moon Jae-in credited Trump's "maximum pressure" approach, including wide-ranging sanctions on North Korea, for the diplomatic thaw.

Trump raised serious doubts about whether diplomacy with Pyongyang could work as recently as October, when he publicly said his former Secretary of State Rex Tillerson was "wasting his time" trying to negotiate Kim.

The White House said this week that it would replace Tillerson with CIA Director Mike Pompeo, who is considered more hawkish on North Korea than his predecessor. The US Senate must confirm Pompeo as top US diplomat.

A source close to the Trump administration told CNN that the reason Trump has put Pompeo at the State Department was because he "wanted a strong team ready for North Korea."