The Americans -- Kim Dong Chul, Kim Hak-song and Kim Sang Duk, also known as Tony Kim -- had been jailed for anti-state activities and placed in North Korean labour camps.
The Americans, Kim Dong Chul, Kim Hak-song and Kim Sang Duk, are travelling back to the US with Secretary of State Mike Pompeo.
Trump, who personally greeted the trio at the Andrews Air Force Base, praised Kim for their release ahead of their summit.
In a letter to the North Korean dictator, the US president says talks are 'inappropriate' based on the open hostility displayed in the recent statement.