WASHINGTON — The United States and North Korea on Sunday kicked off an urgent, behind-the-scenes effort to resurrect a summit meeting between their two leaders by June 12, racing to develop a joint agenda and dispel deep skepticism about the chances for reaching a framework for a lasting nuclear agreement in so little time.



Technical and diplomatic experts from the United States made a rare visit to North Korea to meet with their counterparts, American officials said on Sunday. Before any summit meeting, the American team, led by Sung Kim, a veteran diplomat, is seeking detailed commitments from Kim Jong-un, the North Korean leader, about his regime’s willingness to abandon its nuclear weapons program.



In a tweet Sunday night, President Trump confirmed the meetings in the North Korean part of Panmunjom, a “truce village” in the Demilitarized Zone that separates the two Koreas. He also expressed his administration’s newfound optimism about the meeting, further embracing the conciliatory language both sides have used since he canceled the planned meeting in a bitterly worded letter to Mr. Kim on Thursday.

“I truly believe North Korea has brilliant potential and will be a great economic and financial Nation one day,” Mr. Trump wrote on Twitter after a second straight day of golf at his Virginia club. “Kim Jong Un agrees with me on this. It will happen!”