SEOUL (AFP, REUTERS) - United States President Donald Trump is set to head for the demilitarised zone (DMZ) dividing the two Koreas on Sunday (June 30) and a possible impromptu summit with North Korean leader Kim Jong Un, in what would be a remarkable diplomatic spectacle.

"I'm going to the DMZ and I understand that they want to meet, and I'd love to say hello," Mr Trump told a group of South Korean business leaders including the heads of Samsung, Hyundai and SK Groups, on Sunday.

Telling reporters about a possible third face-to-face meeting between himself and Mr Kim, Mr Trump said: "We'll see. He very much wants to. We are trying to work it out."

Mr Trump added: "It will be very short but that's OK. A handshake means a lot."

The encounter is expected to last only a matter of minutes, said Mr Trump, if Mr Kim accepts the invitation.

South Korean President Moon Jae-in would accompany him to the DMZ, Mr Trump told business leaders.

The first meeting between Mr Trump and Mr Kim in Singapore last year took place in a blaze of publicity - the first-ever encounter between a leader of the nuclear-armed North and a sitting US president, whose forces and their allies fought each other to a stalemate in the 1950-53 Korean War.

That summit produced a vaguely worded pledge about denuclearisation, but a second meeting in Hanoi in February intended to put flesh on those bones broke up without agreement.

Contact between the two sides has since been minimal - with Pyongyang issuing frequent criticisms of the US position - but the two leaders have exchanged a series of letters and Mr Trump turned to Twitter on Saturday to invite Mr Kim to a third diplomatic date.

"If Chairman Kim of North Korea sees this, I would meet him at the Border/DMZ just to shake his hand and say Hello(?)!," Mr Trump tweeted from Osaka in Japan, where he was attending a Group of 20 summit before flying to Seoul.

He later said he would have "no problem" stepping into the North with Mr Kim - in what would be a dramatic re-enactment of the extraordinary scene last year when the young leader invited Mr Moon to walk over the Military Demarcation Line that forms the border between the Koreas.

"Sure I would, I would. I'd feel very comfortable doing that. I'd have no problem," Mr Trump told reporters. It was not clear whether Mr Kim would attend the rendezvous.

In an unusually fast and public response, within hours of Mr Trump's tweet, the North's official KCNA news agency quoted Vice-Foreign Minister Choe Son Hui as saying the offer was "a very interesting suggestion" but that no official request had been received.

Dr Cheong Seong-chang, a senior researcher at the Sejong Institute in Seoul, said the KCNA comments indicated that Mr Kim had "practically accepted" Mr Trump's invitation.

"If he (Kim) isn't interested, he would not release such a statement to begin with," said Dr Cheong.

Speculation grew that something was afoot when US Secretary of State Mike Pompeo skipped a G-20 dinner last Friday without giving a reason.

"We'll see. If he is there, we will see each other for two minutes," said Mr Trump.

Later on Saturday, when he was asked about the meeting at a dinner with Mr Moon in Seoul, he said: "We're gonna see. They're working things out right now."

'Barren no-man's land'

A meeting in the DMZ would make a powerful visual statement, but analysts were divided over its potential impact.

The 4km-wide zone, running for 250km, is where the front line lay when the Korean War ended with a ceasefire rather than a peace treaty, and is described as the world's last Cold War frontier.

"The meeting, however short, will have a huge impact, as the DMZ symbolises the military tension between North Korea and the United States," said Professor Koh Yu-hwan at Dongguk University in Seoul. However Mr Robert Kelly of Pusan National University derided Mr Trump's invitation as "emblematic of why the Trump NK effort is a farce: thrown-together; last-minute; made-for-TV".

It was driven by Mr Trump's "lust for optics and drama rather than substance" and "a photo-op for the 2020 election", he tweeted.

But Professor John Delury of Yonsei University in Seoul said that a meeting in the "barren no man's land that embodies the unhealed wound of post-WWII division, the Korean War, and 70 years of animosity" would help improve ties.

"It's not just about denuclearisation and it's not all about a deal - important as those are," he said. "If Trump and Kim meet and can announce some kind of interim agreement, that's great. If they meet and don't, that's OK too. If in the end they don't meet, it's good that Trump offered to."

'Historic setting'

The DMZ has been a regular stop for US presidents visiting the South, a security ally - although Mr Trump's helicopter was forced to turn back by fog in 2017. And Mr Moon - who will also be going to the DMZ on Sunday - and Mr Kim held their first two summits last year at Panmunjom, a "truce village" on the border.

Mr Trump could leverage the "historic setting" to send a clear message to Pyongyang on what a compromise agreement might look like, said Mr Harry Kazianis of the Centre for the National Interest.

The US could offer to suspend, rather than remove, some of the UN Security Council sanctions in exchange for the full closure of the North's Yongbyon nuclear facility, he suggested.

"Such a formulation would give Pyongyang the economic incentives it needs to jump-start its economy while giving Trump an important foreign policy victory."