SEOUL (Reuters) - U.S. President Donald Trump is set to visit the demilitarized zone (DMZ) separating North and South Korea on Sunday, hoping for a third encounter with North Korean leader Kim Jong Un to revive stalled nuclear talks.

An employee watches a set of TV's broadcasting a news report on a Hanoi summit between North Korean leader Kim Jong Un and U.S. President Donald Trump, in Seoul, South Korea, February 28, 2019. REUTERS/Kim Hong-Ji

Trump arrived in Seoul late on Saturday for talks with South Korean President Moon Jae-in after attending the Group of 20 summit in Osaka, Japan, during which he made a surprise, spur-of-the-moment offer to meet Kim.

If Trump and Kim meet, it would be for the third time in just over a year, and four months since their second summit in the Vietnamese capital Hanoi broke down after they failed to resolve differences over U.S. demands for denuclearization and North Korean demands for easing sanctions.

North Korea has pursued nuclear and missile programs for years in defiance of U.N. Security Council resolutions, and easing tensions with North Korea is one of the U.S. president’s top foreign policy priorities.

Trump made the offer to meet in a message on Twitter about his visit to South Korea.

“While there, if Chairman Kim of North Korea sees this, I would meet him at the Border/DMZ just to shake his hand and say Hello(?)!” Trump wrote.

In response, state news agency KCNA quoted a senior North Korean official several hours later as saying it was a “very interesting suggestion” and would be a “meaningful occasion,” but that North Korea had not received an official proposal.

Moon told Trump during a dinner on Saturday that such a meeting would be an “historic event.” But even if it did not take place, Moon said, the offer would have a “significant outcome” because Trump showed sincerity to Kim.

Trump wanted to visit the DMZ, where Kim and Moon held an historic first summit last year, during a 2017 visit to South Korea, but heavy fog prevented it.

Lee Seok-hyun, a senior lawmaker from Moon’s party, said on Twitter on Saturday that Moon and Trump will likely join Kim on Sunday for a three-way gathering in the Joint Security Area (JSA) within the DMZ.

Moon has championed efforts to end the hostilities between North Korea and the United States, vowing to play a mediator role in nudging Pyongyang into giving up its nuclear weapons in exchange for sanctions relief and security guarantees.

Moon’s press secretary said late on Saturday that a meeting between Trump and Kim would be a “crucial chance” to reinvigorate the talks, but did not say whether Moon would go to the DMZ or meet Kim. Trump said after he landed in South Korea: “We’re working things out right now.”

The JSA, with its cluster of distinctive bright blue buildings, has a chequered history of defections, tension and death. In 1976, axe-wielding North Korean soldiers murdered two American soldiers who were cutting down a poplar tree there to secure a clear view.

Trump, speaking at a news conference in Japan on Saturday, said he would be “very comfortable” stepping across the border into North Korea, as Moon did briefly last year.

Some South Korean analysts said another Trump-Kim encounter would do little to advance progress on denuclearization.

“Trump is trying to get a free hand in controlling peace on the Korean peninsula with his tweets and we can’t let that happen,” said Kim Dong-yup of Kyungnam University’s Institute for Far Eastern Studies in Seoul. “It’s a strategy and technique he adopted to deal with those who are in a weak position in negotiations, and that’s for domestic politics.”

Trump is expected to meet with South Korean business leaders before holding a summit with Moon and visiting the DMZ. He is scheduled to return to Washington on Sunday.

Trump and Kim held an unprecedented summit in Singapore in June last year, agreeing to forge new relations and work towards denuclearization of the Korean peninsula.