North and South Korea begin historic summit

North Korean leader Kim Jong Un and the South's President Moon Jae-in sat down to a historic summit today after shaking hands over the Military Demarcation Line that divides their countries in a gesture laden with symbolism.

"I am happy to meet you," a smiling Moon told Kim before the visitor stepped over the concrete blocks, making him the first North Korean leader to set foot in the South since the Korean War ended in an armistice 65 years ago.

At Kim's invitation the two men briefly crossed hand-in-hand into the North before walking to the Peace House building on the southern side of the truce village of Panmunjom for the summit -- only the third of its kind since hostilities ceased in 1953.

"I came here determined to send a starting signal at the threshold of a new history," Kim told Moon as the meeting began, promising a "frank, serious and honest mindset".

With the North's atomic arsenal high on the agenda, Moon responded that he hoped they would reach "a bold agreement so that we may give a big gift to the whole Korean people and the people who want peace".

It is the highest-level encounter yet in a whirlwind of nuclear diplomacy, and intended to pave the way for a much-anticipated encounter between Kim and US President Donald Trump.

The North's official KCNA news agency said that Kim will "open-heartedly discuss... all the issues arising in improving inter-Korean relations and achieving peace, prosperity and reunification of the Korean peninsula".

It did not mention denuclearisation.

Last year Pyongyang carried out its sixth nuclear blast, by far its most powerful to date, and launched missiles capable of reaching the US mainland.

Its actions sent tensions soaring as Kim and Trump traded personal insults and threats of war.

Moon seized on the South's Winter Olympics as an opportunity to broker dialogue between them, and has said his meeting with Kim will serve to set up the summit between Pyongyang and Washington.

The White House said in a statement it hoped the summit would it would "achieve progress toward a future of peace and prosperity for the entire Korean Peninsula".

Trump has demanded the North give up its weapons, and Washington is pressing for it to do so in a complete, verifiable and irreversible way.

But Seoul played down expectations Thursday, saying the North's technological advances with its nuclear and missile programmes meant any deal would be "fundamentally different in nature from denuclearisation agreements in 1990s and early 2000s".

"That's what makes this summit all the more difficult," the chief of the South's presidential secretariat Im Jong-seok told reporters.