SEOUL, South Korea — President Trump said he would meet on Sunday with Kim Jong-un, North Korea’s leader, at the heavily fortified Demilitarized Zone dividing the two Koreas in an extraordinary last-minute get-together intended to revitalize stalled nuclear talks.
Mr. Kim accepted Mr. Trump’s unorthodox invitation, posted on Twitter just a day earlier, for what will be the third time the leaders have gotten together in person. The encounter will be little more than a brief greeting, not an extended negotiation, but it promises a camera-friendly, history-making demonstration of friendship between countries that have been longtime adversaries.
“We are going to the DMZ border, and we will be meeting Chairman Kim,” Mr. Trump said at a news conference in Seoul with President Moon Jae-in of South Korea. “I look forward to it very much.” He added that there was “a lot of good feeling” between him and Mr. Kim. “He understands me, and I think I understand him,” he said.
It remained uncertain how the handshake between the two leaders would be orchestrated. Mr. Trump said before leaving Osaka, Japan, on Saturday that he would be perfectly willing to cross over the line into North Korea if need be, which would make him the first sitting American president to visit the long-isolated country, with whom the United States remains technically still at war from the conflict of the 1950s.
Mr. Kim crossed the DMZ in April 2018 to meet with Mr. Moon, becoming the first North Korean leader to step over the line since fighting between the countries ended in 1953. Former Presidents Jimmy Carter and Bill Clinton each visited North Korea, flying into its capital, Pyongyang, but only after they left office.
Mr. Trump met with Mr. Kim in Singapore in June 2018, the first time American and North Korean leaders had met since the war, and produced vague promises to pursue an end to Pyongyang’s nuclear arsenal. Their second summit meeting, in Hanoi, Vietnam, ended in failure in February when the two leaders could not agree on a concrete way to pursue that goal.
North Korean leaders went dark after the collapse of the talks, refusing to respond to either the Americans or the South Koreans amid conflicting reports about the fate of the negotiators blamed by Mr. Kim for the failure. North Korea also launched short-range missiles in May in violation of United Nations restrictions, a move that was seen as a reflection of Mr. Kim’s frustration over the stalled negotiations.
In recent weeks, however, the North Korean government has re-emerged on the world stage as Mr. Kim exchanged letters with Mr. Trump and met separately with President Vladimir V. Putin of Russia and President Xi Jinping of China in what was seen as a signal of its interest in resuming diplomacy.
American officials have said they did not think a third meeting between Mr. Trump and Mr. Kim should be arranged unless a substantive agreement could be negotiated beforehand to avoid another setback. But Mr. Trump said that since he was already planning to visit the DMZ during his trip to South Korea this weekend, he decided it was worth seeing if Mr. Kim would agree to a short greeting.
“It’s just a step,” Mr. Trump said. “It might be an important step or it might not.” He added: “There’s a good feeling, so it could be very good. As far as another meeting, let’s see what happens today before we start thinking about that.”
Mr. Moon, who has staked his presidency on improving relations with the North, showered Mr. Trump with praise for reaching out, declaring that “the flower of peace is truly blossoming” and describing himself as “very overwhelmed with emotion” about the development.
“President Trump is the maker of peace on the Korean Peninsula, you really are the peacemaker of the Korean Peninsula,” Mr. Moon said. “I hope that this meeting with Chairman Kim at Panmunjom will bring hope to the people of South and North Korea and it will be a milestone in the history of humankind toward peace.”
But whatever good may be generated by the symbolic encounter at the DMZ, enormous differences remain between the two sides that have prevented a deal.
Mr. Trump has insisted that Mr. Kim give up his entire nuclear arsenal and program, while many experts, including American intelligence analysts, doubt that the North Korean leader is genuinely willing to do so.