In the past, that has meant Washington would have to withdraw all of its troops from South Korea, a condition no U.S. president has been willing to consider.
In a letter to U.N. Secretary-General Antonio Guterres last month, he urged the United Nations not to remain silent about what he called "the USA risky game of aggravating (the) situation in and around the Korean peninsula and driving the whole world into a possible disaster of nuclear war".
"We have a very big trade deficit with them, and we protect them", Trump reportedly said of South Korea, according to audio obtained by the Washington Post.
Ri's delegation included Choe Kang Il, deputy director general of the foreign ministry's North America section.
The U.S. -North Korea summit talks were brokered by Moon's envoys, who met with Kim Jong Un during a March 5-6 Pyongyang trip.
The talks "will focus on Sweden's consular responsibilities as a protecting power for the United States, Canada and Australia", and Ri and Wallstrom will discuss the security situation on the Korean Peninsula, the ministry said.
Trump and President Moon Jae-in discussed preparations for their upcoming engagements with North Korea and agreed that "concrete actions" were the key to achieving denuclearisation of the Korean peninsula, the White House said in a statement on Friday.
North Korea has yet to publicly confirm the summit plans, and the venue for the meeting remains up in the air, although a rare visit by the North's top diplomat to Sweden on Friday fueled speculation the Scandinavian nation might play host.
The North Korean minister is expected to meet with his Swedish counterpart Margot Wallstrom.
His move is attracting attention as Pyongyang has yet to officially respond to US President Donald Trump's acceptance of North Korean leader Kim Jong Un's invitation to talk.
It comes after Kim has referred to Trump as a "senile dotard" and Trump has repeatedly referred to the North Korean leader as "Little Rocket Man".
For his part, Moon said inter-Korean relations could advance only if North Korea improves its ties not just with the USA but Japan as well, according to South Korean sources.
Kim will agree to dismantle his nuclear capability only if the USA withdraws all its military from South Korea and ceases military exercises off the Korean coast.
"The Swedes have this long-established presence in North Korea, so since the 1990s, they've particularly looked after United States interests", Hoare told CNN. They also agreed that a "brighter future is available for North Korea, if it chooses the right path", the White House stated. So Moon was forced to go more hard-line than he probably wanted and to join Trump's sanctions and pressure campaign against Pyongyang.
South Korea diplomats said North Korea has agreed to discuss "denuclearization" at the talks, planned for May, though the hermit kingdom has long demanded a removal of USA troops in its southern neighbor in exchange.
The two allies will also arrange a timetable on JapanesePrime Minister Shinzo Abe's trip to the USA expected early next month andsummit talks with Trump in Washington.
And according to Yonhap, Moon stressed that improvement in Pyongyang's ties with Tokyo and Washington was needed to help end the crisis with North Korea. "This trip is also aimed at making sure of that".