He later added: "We very much appreciate that he allowed them to go before the meeting".
But the President saw the release of the three Americans as yet another reason for optimism as he prepares for the summit.
The three men had been jailed for anti-state activities and placed in labour camps.
Mr Trump said it was a "special night for these really great people" as they arrived at the Andrews Air Force Base near Washington.
He said: "My proudest achievement will be - this is part of it - when we denuclearise that entire peninsula". "It's a very important thing to all of us".
It came during a visit to Pyongyang by Mr Pompeo to arrange details of the meeting between Mr Trump and Kim Jong-un.
Between Singapore and the DMZ, US officials have shown preference for the former as they see the country's neutrality and infrastructure as advantages over locations nearer to Pyongyang.
There has been no word from North Korea on its agenda or what it might offer, although a key issue is likely to be the presence of 30,000 U.S. military personnel in South Korea, along with the removal of sanctions.
At least 20 dead after dam burst in Kenya
Among villages affected are those in the farmlands of Nyakinyua, Endao, and Arutani where hundreds of people were displaced. The local people are now concerned about the condition of the other two dams, which are also reportedly full.
Mooy's Huddersfield safe as Chelsea's UCL hopes dented
Liverpool only need a draw against Brighton on Sunday to ensure a top-four finish, following Chelsea's 1-1 draw with Huddersfield on Wednesday night.
Phil Mickelson says Tiger Woods played best golf ever
One year they were in the locker room at the Byron Nelson Classic when Mickelson challenged Woods to anything at their disposal. Woods is on a comeback after spinal fusion surgery to ease nagging back pain that cost him most of the past two PGA campaigns.
The Americans should never have been detained in the first place, Mr Schumer said on the Senate floor.
South Korean Foreign Minister Kang Kyung-wha will travel to the United States this week for talks with Secretary of State Mike Pompeo on North Korea and alliance issues, her ministry announced Thursday.
Singapore, nearly 3,000 miles south of Pyongyang, maintains diplomatic relations with North Korea which has an embassy and ambassador in the country.
Singapore is the likely site for the historic meeting between Trump and Jong Un later this month or in early June, and Pompeo said it would last one day and possibly a second. More than a dozen abductees still remain missing, according to the Japanese government. Trump said on Twitter.
Once dubbed an "Asian Switzerland", Singapore represents neutral ground for the two leaders.