Im added that he could not rule out the possibility that Moon may meet U.S. President Donald Trump after the inter-Korean summit but before Trump's planned summit with North Korean leader Kim Jong Un in May.
The official announcement by the Swedish MFA is that the two diplomats will discuss the "consular responsibilities of Sweden as a defender of the interests of the United States, Australia and Canada" in North Korea and the "Korean Peninsula Security Situation" will also be discussed.
Sweden, whose embassy represents United States 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.
Sweden has had diplomatic relations with North Korea since 1973, and is one of the few Western countries to have an embassy in Pyongyang.
"The main actors South Korea, North Korea, China, the USA and Japan have to agree on the substance", he said.
"(We) will make efforts to maintain communication without any problem", she said.
Before a date or a venue for the summit can be set, North Korea will have to publicly confirm that it sent the invitation and intends to honour it, by attending a meeting to discuss giving up its nuclear arsenal.
Man feared dead after chemical plant explodes in Texas
Smoke from the fire blew towards Fort Worth and Weatherford, and the Environmental Protection Agency is monitoring air emissions. Although there is a fertilizer plant adjacent to the Tri-Chem plant, Wilson said there's "no known threat to their facility".
Trump and Moon "agreed that concrete actions, not words, will be the key to achieving permanent denuclearization of the Korean peninsula, and President Trump reiterated his intention to meet with North Korean leader Kim Jong Un by the end of May", the White House said.
Ri left Pyongyang and flew into a Beijing airport on Thursday.
The release of Otto Warmbier, the United States student who was imprisoned in North Korea, was mediated by Swedish diplomats, for example.
The US State Department said it was aware of the meeting in Stockholm, but that Washington would not be taking part. "We'll see what happens next", Wallstrom told reporters after Friday's talks.
The isolated state has always maintained it will continue to develop its nuclear weapons as a deterrent against USA aggression but, according to South Korea, it later said it was open to abandoning the programme if the security of its regime was guaranteed.
The trip by Ri is being closely watched because a huge amount of preparation needs to be done before the summit.
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.