Kim said he released the three Americans yesterday after an "official suggestion" from Trump. We looked them straight in the eye and they said to us verbatim, 'God bless America.
Next month Trump and North Korea leader Kim Jong-un are due to hold a historic face-to-face meeting.
The release gave Trump a chance to tout a diplomatic achievement just a day after his decision to pull out of the Iran nuclear deal drew heavy criticism from European allies and others.
In 2015, Singapore it was the site of another unprecedented summit between two leaders burdened with a legacy of mutual distrust: Chinese President Xi Jinping and rival Taiwan's then-President Ma Ying-jeou, the first such meeting since the founding of the People's Republic of China in 1949.
When asked how it feels to be home, one of the detainees said through a translator "it's like a dream and we're very, very happy".
The fate of the three Korean-Americans had been among a number of delicate issues in the run-up to summit, which is being planned for late May or early June.
State media reported that "Supreme Leader Kim Jong Un warmly greeted Mike Pompeo and sincerely congratulated him on his recent official assumption as secretary of State". Rodong Sinmun, the official newspaper of the Workers' Party of Korea's Central Committee, accused the U.S.in a commentary Wednesday of holding on to a "Cold War way of thinking" and being "rude", according to the state-run Korean Central News Agency.
"All I'll say is that the meeting has been agreed to, but obviously, it could be halted for any number of reasons", Shah said with a note of caution to the North Koreans.
The men's families were informed of their release after Pompeo called Trump once his plane had cleared North Korean air space.
The U.S. had long demanded that North Korea free the men, Kim Dong-chul, Kim Hak-song and Tony Kim, who had been held on charges of espionage and "hostile acts".
"Though we're not quite back home yet, I welcomed them back", Pompeo told Associated Press.
"You're never certain exactly what you're going to get into when you're dealing with certain governments that you don't always have a friendly relationship with", she said.
A location and date have been set for the meeting, Trump said, but the details have not been released to the public yet. And there are a number of things - provocative actions, for example, from North Korea, would not be received well. "This is not the result of sanctions that have been imposed from outside". Previous U.S. efforts to negotiate an end to the North's nuclear weapons program failed under Presidents Bill Clinton and George W. Bush.