The two Koreas have agreed to rid their peninsula of nuclear weapons but failed to provide any new specific measures how to achieve that.
Pyongyang and Seoul also said they will jointly push for talks with the United States and potentially China to officially end the 1950-53 Korean War through a peace treaty.
In a joint statement issued after their leaders’ talks Friday says the two Koreas confirmed their goal of achieving “a nuclear-free Korean Peninsula through complete denuclearisation”.
Live updates from the Korean summit
Pictures: Korea's historic summit
South Koreans captivated by 'cute' Kim
North Korean leader Kim Jong-un and South Korean president Moon Jae-in said the Koreas will push for three-way talks including Washington or four-way talks that will involve China as well to convert the armistice into a peace treaty and establish permanent peace on the Korean Peninsula.
The Koreas said they hope the parties will be able to declare an official end to the war by the end of this year.
North Korea has placed its nuclear weapons up for negotiations. It has previously used the term “denuclearisation” to say it can disarm only when the United States withdraws its 28,500 troops in South Korea.
The statement did not say what other specific disarmament steps North Korea would take.
Earlier, with a single step over a weathered, cracked slab of concrete, Mr Kim Jong-un made history on Friday by crossing over the world’s most heavily armed border to greet the South Korean president for talks.
Mr Kim then invited Mr Moon to cross briefly back into the north with him before they returned to the southern side.
Those small steps must be seen in the context of the last year – when the United States, its ally South Korea and the North seemed at times to be on the verge of nuclear war as the North unleashed a torrent of weapons tests – but also in light of the long, destructive history of the rival Koreas, who fought one of the 20th century’s bloodiest conflicts and even today occupy a divided peninsula that’s still technically at war.
“I feel like I’m firing a flare at the starting line in the moment of [the two Koreas] writing a new history in North-South relations, peace and prosperity,” Mr Kim told Mr Moon as they sat at a table, which had been built so that exactly 2018 millimeters separated them, to begin their closed-door talks.
Read more: Live updates from the Korean summit
Mr Moon responded that there were high expectations that they produce an agreement that will be a "big gift to the entire Korean nation and every peace loving person in the world".
The two leaders vowed to have more meetings, according to Mr Moon’s spokesman, Yoon Young-chan, with Mr Kim joking that he would make sure not to interrupt Mr Moon’s sleep anymore, a reference to the North’s drumbeat of early morning missile tests last year.
Mr Kim also referred to a South Korean island that North Korea attacked with artillery in 2010, killing four, saying the residents of Yeonpyeong Island who have been living in fear of North Korean artillery have high hopes the summit will help heal past scars. Mr Kim said he’d visit Seoul’s presidential Blue House if invited.
In the afternoon, Mr Moon and Mr Kim got together to plant a pine tree on the grounds of the Truce Village.
The leaders poured a mixture of soil and water from both countries and unveiled a stone plaque that was engraved with a message saying “Peace and Prosperity Are Planted.” The tree dates to 1953, the year the Korean War ended in an armistice.
Earlier, both leaders smiled as Mr Moon grasped Mr Kim’s hand and led him along a blindingly red carpet into South Korean territory, where schoolchildren gave Mr Kim flowers and a honour guard stood at attention for inspection, a military band playing traditional Korean folk songs beloved by both Koreas.
It’s the first time a North Korean leader has crossed over to the southern side of the Demilitarised Zone since the Korean War ended in 1953.
Mr Kim’s news agency said that the leader would “open-heartedly” discuss with Mr Moon “all the issues arising in improving inter-Korean relations and achieving peace, prosperity and reunification of the Korean peninsula” in a “historic” summit.
The greeting of the two leaders was planned to the last detail. Thousands of journalists were kept in a huge conference centre well away from the summit, except for a small group of tightly controlled pool reporters at the border. Mr Moon stood near the Koreas’ dividing line, moving forward the moment he glimpsed Kim, dressed in dark, Mao-style suit, appearing in front of a building on the northern side.
They shook hands with the border line between them. Mr Moon then invited Mr Kim to cross into the South, and, after he did so, Mr Kim grasped Mr Moon’s hand and led him into the North and then back into the South. They took a ceremonial photo facing the North and then another photo facing the South.
Two young school children from the Daesongdong Elementary School, the only South Korean school within the DMZ, greeted the leaders and gave Mr Kim flowers.
The leaders then saluted an honour guard and military band, and Mr Moon introduced Kim to South Korean government officials. Mr Kim returned the favour, introducing Mr Moon to the North Korean officials accompanying him.
They then took a photo inside the Peace House, where the summit was to take place, in front of a painting of South Korea’s Bukhan Mountain, which towers over the South Korean Blue House presidential mansion.
Mr Kim’s sister, Kim Yo Jong, was by his side throughout the ceremony, handing him a pen to sign a guestbook, taking the schoolchildren’s flowers from his hand and scribbling notes at the start of the talks with Mr Moon.
The White House said in a statement earlier that it was “hopeful that talks will achieve progress toward a future of peace and prosperity for the entire Korean Peninsula. ... (and) looks forward to continuing robust discussions in preparation for the planned meeting between President Donald J Trump and Kim Jong-un in the coming weeks.”
Read more: Trump says North Korea has made major nuclear concessions
Mr Kim, the third member of his family to rule his nation with absolute power, remains eager, both in this meeting and in the Trump talks, to talk about the nearly 30,000 heavily armed US troops stationed in South Korea and the lack of a formal peace treaty ending the Korea War – two factors, the North says, that make nuclear weapons necessary.
South Korea has acknowledged that the most difficult sticking point between the Koreas has been North Korea’s level of denuclearisation commitment. Mr Kim has reportedly said that he wouldn’t need nuclear weapons if his government’s security could be guaranteed and external threats were removed.
Mr Kim and Mr Moon enjoyed each other’s company in the jointly controlled village of Panmunjom near the spot where a defecting North Korean soldier fled south last year in a hail of bullets fired by his former comrades.