The US president broke the news on Twitter, writing: "We will both try to make it a very special moment for world peace!"
Kim Hak Song was also associated with Pyongyang University of Science and Technology and was detained in North Korea in May 2017. The three freed Americans, along with President Trump and the First Lady emerged from the plane to applause and cheers.
Earlier on Thursday, Mr Trump thanked Mr Kim for releasing three Americans from captivity, saying he believes Kim wants to reach an agreement on denuclearising the Korean peninsula.
Such a program should involve partners around the world, such as South Korea and Japan, according to the chief USA diplomat. "But the true honour is going to be if we have a victory in getting rid of nuclear weapons", he said.
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The United States aspires to have North Korea as a "close partner" and not an enemy, the U.S. secretary of state has said.
Welcoming the three Americans at a military base outside Washington early Thursday, Trump said of Kim, "I really think he wants to do something". During the meeting, Kim and Moon signed a joint declaration, agreeing to take measures to support global efforts aimed at denuclearizing the peninsula and proceeding with reunion programs for separated Korean families.More news: Hottest Bank Holiday Monday in 40 years
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It also avoids any embarrassment for Kim, as North Korea's ageing jets limits the distance he can travel without stopping to refuel.
Kang said the worldwide community will not ease or lift sanctions on North Korea until the world sees visible and meaningful action by Pyongyang toward denuclearization.
However, his comments made clear that the two sides remained far apart on the key issue of what they mean by denuclearization.
The summit meeting between Trump and Kim will come after almost six months of a pivot toward diplomacy from North Korea and Kim Jong-un.
Regarding the conflict between Iran and Israel in Syria, he said that China has taken note of relevant reports and hoped relevant parties would keep calm and exercise restraint and jointly safeguard regional peace and stability.