With a smile on his face, President Moon was waiting to greet the young North Korean leader at concrete curbs that serve as the Military Demarcation Line.

The two leaders had a historic handshake right across the border at 9:29 a.m., followed by Kim's border crossing amid intense media coverage to capture the historic moment of the two leaders' encounter.

Then, Kim made an unexpected hand gesture to Moon to step to the North Korean side of Panmunjom, an offer dearly accepted by Moon. The two leaders, hand in hand, briefly crossed the border together and returned to the South's side.

Kim has become the first North Korean leader to set foot on South Korean soil since the end of the 1950-53 Korean War.

Panmunjom, 50 kilometers north of Seoul, has a symbolic meaning as the venue for inter-Korean talks as it is the place where the Armistice Agreement was signed at the end of the war.

The two Koreas remain technically at war as the conflict ended in a truce, not a peace treaty.

Kim Jong-un made his international debut last month when he made a surprise visit to China for a summit with Chinese President Xi Jinping. But his trip was an "unofficial" visit and not broadcast live.

After crossing the border, Kim received an official welcoming near the Freedom House, a South Korean building that hosts a communication line office.

Kim reviewed a South Korean honor guard while a ceremonial band played the tune of "Arirang," a Korean folk ballad. It was the first time that a North Korean leader inspected a South Korean honor guard.

The Friday summit is only the third inter-Korean meeting following those in 2000 and 2007, both of which were held in Pyongyang.

North Korea's state media reported early Friday that Kim "will open-heartedly" discuss pending inter-Korean issues with Moon at the summit. It will be followed by a summit between Kim and US President Donald Trump probably in May or early June.

At the Peace House, the main venue for the talks, Kim Jong-un left a message in a guest book that read, "A new history begins from now on. At the starting point of an era of peace and history."

Meanwhile, Kim was accompanied by nine key ranking officials, including his younger sister Kim Yo-jong, on his trip to the border.

Kim Yo-jong, the first vice director of the ruling Workers' Party of Korea, was spotted accompanying her brother from nearby at Panmunjom, effectively serving as Kim's chief of staff.

She has been involved in key inter-Korean events including the North's dispatch of a high-level delegation to the opening ceremony of the PyeongChang Winter Olympics in February.(Yonhap)