The historic trilateral meeting of leaders of the two Koreas and the United States on Sunday was realized with the US point man on North Korea and North Korean officials working behind the scenes well into the night on Saturday.

US Special Representative for North Korea Biegun met Saturday with North Korean officials at Tongilgak, or Unification Pavilion, on the northern side of the Joint Security Area to coordinate the surprise meeting.

With Alison Hooker, a US National Security Council official specializing in Korean affairs, Biegun flew to the border village in the Demilitarized Zone via helicopter in the night and met with officials of North Korea to discuss security and the movement of leaders.

While it has not been confirmed who represented the North Korean side, it was reportedly neither Choe Son-hui, first Vice Minister of Foreign Affairs nor Kim Hyok-chol, special envoy to the United States.

Kim Chang-son, the chief secretary of North Korea’s Secretariat of the State Affairs Commission, is thought to have been one of the officials present at the Tongilgak meeting. Kim was spotted in the sidelines of the North Korean leader when he met with Trump in Panmunjom on Sunday.

The two US officials who were initially scheduled to attend the Blue House dinner hosted by South Korean President Moon Jae-in on Saturday were absent at the event, suggesting that they may have been at Panmunjom to coordinate the next day’s event.

While Trump’s visit to Seoul and the DMZ was scheduled months ahead, the idea of meeting the North Korean leader had come to his mind only on Saturday, the US president said. In a tweet, Trump made an offer to the North Korean leader to meet at the inter-Korean border.

“After some very important meetings, including my meeting with President Xi of China, I will be leaving Japan for South Korea (with President Moon). While there, if Chairman Kim of North Korea sees this, I would meet him at the Border/DMZ just to shake his hand and say Hello(?)!,” he tweeted.

“Yesterday, I was just thinking, hey I’m here, let’s see whether or not we can say hello to Kim Jong-un. And I put out the word and he (Kim) got back, and he wanted to do it from the beginning and so did I,” Trump said, standing side to side with Kim on the southern part of the Panmunjom, Sunday.

Praising their close relationship, Kim also said their encounter was finalized in a day.

“Our (great) relationship will make good things that others cannot expect. I am confident (our relationship) will become the miraculous power that will (help) overcome difficulties,” Kim said.

Trump sought to visit the DMZ during his first visit to Seoul in November 2017, but the plan was canceled at the time due to bad weather.

By Jo He-rim (herim@heraldcorp.com)