The official KCNA news agency carried the text of the leaders' Panmunjom Declaration in full and said the encounter opened the way "for national reconciliation and unity, peace and prosperity".

In the document North Korean leader Kim Jong Un and the South's President Moon Jae-in "confirmed the common goal of realising, through complete denuclearisation, a nuclear-free Korean Peninsula".

That phrase was included in the KCNA text as well.

For years, Pyongyang insisted it would never give up the "treasured sword" of its nuclear arsenal, which it says it needs to defend itself against a possible US invasion.

But it has offered to put it up for negotiation in exchange for security guarantees, according to Seoul -- although Kim made no public reference to doing so at Friday's spectacular summit.

When Kim stepped over the military demarcation line that divides the peninsula he became the first North Korean leader to set foot in the South since the Korean War hostilities ceased in 1953 with an armistice rather than a peace treaty.

He then persuaded Moon to step into the North, and the two leaders shared a day of smiles, intimate moments, and a half-hour-long one-on-one conversation.

The North has made rapid progress in its weapons programmes under Kim, detonating its sixth and most powerful nuclear test last year and launching missiles capable of reaching the US mainland, in moves that triggered increasingly strict UN Security Council sanctions against the regime.

Kim and US President Donald Trump traded personal insults and threats of war, sending tensions soaring before Moon seized on the Winter Olympics to broker dialogue, beginning a dizzying whirl of diplomacy that led to Friday's meeting in the Demilitarized Zone.

Analysts and diplomats say that a combination of factors were behind Pyongyang's change of heart, including feeling that it was in a position to negotiate from strength, the looming impact of sanctions, and fear of potential US military action.

But KCNA gave Kim the credit.

"The historic meeting at Panmunjom came to be realised thanks to the supreme leader's ardent love for the people and will for self-determination" independent of outside influence, it said.

Washington is pressing Pyongyang to give up its weapons in a complete, verifiable and irreversible way, and analysts say that meaningful progress will depend on the outcome of Kim's much-anticipated summit with Trump in the coming weeks.