The bombshell news, announced by a South Korean delegation at the White House on Thursday night, was met with wary optimism by China and United States allies in the region. It puts them on the same playing field as the United States. He's oscillated between threats and insults directed at Kim and more conciliatory rhetoric.
According to South Korea's presidential National Security Director Chung Eui-yong, who led a 10-member diplomatic delegation, North Korea expressed "definite" interest in denuclearisation, though analysis suggests little scope for substantive agreement.
Starting in 2003, Beijing hosted several rounds of "Six Party Talks", involving North and South Korea, China, Russia, Japan and the US, which ended in failure when Pyongyang withdrew in 2009.
Yun's boss in the State Department Bureau of East Asian and Pacific Affairs is respected China specialist Acting Assistant Secretary of State Susan Thornton. This is despite repeated reports of China/Russia assisting North Korea to evade sanctions.
There has been breakneck progress in relations between the two Koreans since Kim reached out to Seoul in his New Year's speech and indicated his readiness to send North Korean athletes, officials and cheerleaders to the Pyeongchang Winter Olympics.
Chief Cabinet Secretary Yoshihide Suga was right to note that previous talks on denuclearization have failed and that it is "extremely important" that North Korea show a commitment to and concrete actions toward abandonment of its nuclear and missile development in a complete, verifiable and irreversible way.
North and South Korea, where the United Sates stations 28,500 troops, are technically still at war after their 1950-53 conflict ended in a ceasefire, not a truce.
In February, Trump also announced the United States' "heaviest ever" sanctions against North Korea to prevent it from further developing its nuclear programme.
For his part, Sanders, a presidential contender in the 2016 election, said that he is "very anxious about North Korea's nuclear capability" and seemed skeptical that Trump is taking diplomacy seriously.
Analysts say North Korea has been seeking a summit with American leaders as a way to secure worldwide legitimacy, something that has prevented past USA administration's from taking Pyongyang up on its invitations.
Chung said the US President's "leadership" and his administration's pressure on the North Korean regime had "brought us to this juncture".
This was the first time that South Korean officials met with Kim Jong-un in person since he assumed power after his father's death in late 2011.
"We consider it to be a step in the right direction".
"This has compelled the North to the table", said Kinzinger, while urging caution.
Washington's contacts with Pyongyang are limited, but a year ago Yun successfully negotiated the return of a U.S. prisoner, college student Otto Warmbier, from a northern jail. "We just need to be very clear-eyed and realistic about it", Tillerson said from Ethiopia on Thursday. I forget specifically what it was called, but it was an agreement between the U.S. and North Korea to make things better between the two countries.
"So if there's going to be a period of the next two or three or four months of diplomacy, I think that's positive", Burns said.
Envoy Chung Eui-yong, head of Seoul's National Security Office, will travel to China as well as Russian Federation following his Washington trip where he announced Trump will meet Kim.
The date and location of the meeting have not yet been determined.