The armistice was signed by the USA -led United Nations Command, the North and China in July 1953.
Trump told Reuters he was still hoping for an unprecedented meeting with Kim to push for North Korean "denuclearization", although he conceded it might require more time to reach that goal. The date for the talks has not yet been set, however, with the Kremlin spokesman Dmitry Peskov noting that "it is too early" to talk about the meeting between Kim and Putin.
Russian Federation has appeared to be on the fringes of a flurry of diplomacy, but Lavrov's visit was a move to raise its profile in global efforts to ease tension on the Korean peninsula, said Artyom Lukin, a professor at Far Eastern Federal University in Vladivostok.
Kim Yong Chol, the former military intelligence chief and one of the North Korean leader's closest aides, landed midafternoon on an Air China flight from Beijing. Pompeo was due to hold a news conference, and a North Korean official said the delegation was making a decision on when to head to Washington.
But, after their morning of discussions, Pompeo tweeted: "Substantive talks with the team from #NorthKorea".
Kim Jong Un's comment on USA hegemonism wasn't carried by the North's official Korean Central News Agency, which targets an external audience.
Kim, vice chairman of the Workers' Party's Central Committee and director of the committee's United Front Department, attended a dinner with Pompeo for 90 minutes at the Manhattan residence of the U.S. deputy representative to the United Nations.
State Department spokeswoman Heather Nauert said Thursday that Pompeo told her that the meetings "were great last night, but there is still a lot of work to be done".
"I believe they are contemplating a path forward".
Asked by reporters about the contents of Mr. Kim's letter, the president initially described it as "very nice" and "interesting". "It is very important to them". "But the relationship is building and it is a very positive thing". "We will see what we will see". It is all a process.
"I think we are looking for something historic", said the official, speaking anonymously to discuss the private meetings. Maybe you have to have a second or third, and maybe we'll have none, but it's in good hands.
But Kim Jong Un, in a meeting with Russia's foreign minister on Thursday (Friday NZT), complained about "US hegemonism", a comment that may complicate the discussions in NY. "Remember what I say, we will see what we will see".
North Korea's flurry of diplomatic activity following a torrid run in nuclear weapons and missile tests in 2017 suggests that Kim Jong Un is eager for sanctions relief to build his economy and the worldwide legitimacy the summit with Trump would provide. North Korea and the United States are still technically at war and have no diplomatic ties because the 1950-53 Korean War ended with an armistice, not a peace treaty.
Speaking after the meeting, Trump said: "We are going to deal and we are really going to start a process", Trump told reporters on Friday.