North Korea's leader Kim Jong-un and the South's president Moon Jae-in will meet at the Military Demarcation Line that divides the peninsula before their summit tomorrow.

Mr Moon will greet his visitor at the concrete blocks that mark the border between the two Koreas in the Demilitarized Zone, the chief of the South's presidential secretariat Im Jong-seok said.

When Mr Kim steps over the line he will become the first North Korean leader to set foot in the South since the Korean War ended 65 years ago.

The meeting will be only the third of its kind, following summits in Pyongyang in 2000 and 2007.

It will be the high point so far of a rapid diplomatic rapprochement on the peninsula, ahead of a much-anticipated meeting between Mr Kim and US President Donald Trump.

The North's nuclear arsenal will be high on the agenda. It has made rapid progress in its weapons development under Mr Kim, who inherited power from his father in 2011.

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

It sent tension soaring as Mr Kim and Mr Trump traded personal insults and threats of war.

Mr Moon seized on the South's Winter Olympics as an opportunity to try to broker dialogue between them.

But Mr Im played down expectations, saying that the North's technological advances meant deal would need to be "fundamentally different in nature from denuclearisation agreements reached in the 1990s and early 2000s".

"That's what makes this summit all the more difficult," he added.

"The difficult part is at what level the two leaders will be able to reach an agreement regarding (the North's) willingness to denuclearise and how it will be expressed in text."

In the past, North Korean support for the "denuclearisation of the Korean peninsula" has been code for the removal of US troops from the South and the end of its nuclear umbrella over its security ally - prospects unthinkable in Washington.

Mr 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.

In recent days, South Korea has promoted the idea of a path towards a peace treaty to formally end the 1950-53 Korean War, which stopped with a ceasefire, but Mr Im did not mention the issue.

Reunions of families left divided by the conflict could also be discussed, and Mr Moon has told Japanese Prime Minister Shinzo Abe that he would raise the emotive subject of Japanese citizens kidnapped by the North's agents.

Mr Kim will be given a military honour guard and the two leaders will walk to the Peace House, a glass and concrete building on the southern side of the truce village of Panmunjom where the summit will be held.

Mr Kim will sign the guest book before the morning session starts, Mr Im said, describing the occasion as a "summit for peace and prosperity on the Korean peninsula".

The North's group will cross back to its side for lunch, and before the afternoon session the two leaders will plant a pine tree together.

The soil will come from Mount Paektu, on the North's border with China, and Mount Halla, on the South's southern island of Jeju.

A joint statement will be issued after they sign an agreement. A banquet and farewell ceremony will follow in the evening before Mr Kim returns to the North.