After the two leaders pledged new steps aimed at salvaging nuclear talks on Wednesday, Moon and Kim chose to use the final day of their three-day summit to go up the symbolic mountain on the Chinese border together.
South Korean President Moon Jae-in and North Korean leader Kim Jong-un yesterday announced a sweeping set of agreements after their second day of talks in Pyongyang that included a promise by Kim to permanently dismantle the North's main nuclear complex if the U.S. takes corresponding measures, to accept global inspectors to monitor the closing of a key missile test site and launch pad, and a vow to work together to host the Summer Olympics in 2032.
Pompeo welcomed Wednesday's agreement between the two Koreas to denuclearise the peninsula.
It was the first time a South Korean head of state ever addressed North Korean citizens directly.
"I'm concerned South Korea's visit is going to undermine efforts by @SecPompeo and Ambassador @nikkihaley to impose maximum pressure on the North Korean regime", Graham tweeted yesterday.
"We have agreed to make the Korean Peninsula a land of peace that is free from nuclear weapons and nuclear threat", Kim said as he stood by Moon's side at the guesthouse where Moon is staying.
The hope is that it will kickstart talks between the USA and North Korea which have stalled.
Moon traveled to Pyongyang Tuesday with the goal of breaking an impasse between North Korea and the US over the pace of Pyongyang's intentions in ending its nuclear and ballistic missile programs.More news: NAB decides to challenge suspension of Sharifs' jail terms
The sudden revival of diplomacy comes amid doubts expressed by US President Donald Trump's administration on North Korea's willingness to negotiate in good faith after a June summit between Trump and Kim yielded few tangible results. They said the North was also willing to close its main nuclear complex if the United States took unspecified "reciprocal action".
Kim also pledged establishing closer ties with the South.
"I now propose that we completely eliminate the hostility of the past 70 years and take a big step forward in peace so that we can become one again".
Some US officials were deeply sceptical. Moon also appeared to be making good on his proposals to help build up the North's infrastructure and open cross-border rail links.
United States officials suggested Kim was trying to ease the economic pressure on him to curb his nuclear programmes and to undercut the rationale for U.S. troops being based in South Korea by improving relations with Seoul. "I promised President Moon Jae-in that I will visit Seoul in the near future", he said.
Moon is the first South Korean leader to visit Pyongyang in 11 years. Their trip to the mountain on the North Korean-Chinese border, and the striking photo-op that will resonate in both Koreas, followed a day of wide-ranging agreements they trumpeted as a major step toward peace.
"(Moon) would add much legitimacy to Kim, who had never had any summit with a foreign leader until early this year", said Seo Yu-suk, a research manager at the Institute of North Korean Studies in Seoul.