Mr Pompeo had arrived in the North Korean capital, Pyongyang, earlier on Wednesday from Japan and headed to its Koryo Hotel for meetings. He said he is looking forward to the meeting and believes it is going to be a great thing for North Korea. Their arrests were widely seen as politically motivated and had compounded the dire state of relations over the isolated nation's nuclear weapons.
The president cautioned, however, that the summit could still be scuttled. That contradicted Trump, who has said repeatedly that his pressure tactics brought North Korea to the negotiating table.
Asked if he hopes to win the Nobel Peace Prize, Mr. Trump replied, "I want victory for the world, that's the only prize I want".
The release capped a dramatic day of diplomacy in Pyongyang for Pompeo.
They had been held for periods ranging between one and two years.
Pompeo says the three American detainees freed as a goodwill gesture seem to be in good health "given all they have been through". He died days later.
Kim Dong Chul was arrested in 2015 for spying on behalf of South Korea, he told CNN in January 2016. His parents have filed a wrongful death lawsuit, accusing the government of torturing and killing their son.
The family members of the two educators have said their loved ones are innocent.
The news of the release comes as U.S.
He did not mention that two of the Americans had been detained after he became President.
The trip is Pompeo's second to North Korea this year. He was detained last May for alleged anti-state activities.
Tony Kim's family released a statement thanking "all of those who have worked toward and contributed to his return home". He taught business accounting at the Pyongyang University of Science and Technology. He was accused of committing unspecified criminal acts meant to overthrow the government.
President Donald Trump's decision Tuesday to scrap the Iran nuclear deal and his parallel pursuit of securing an agreement with North Korea to end its nuclear program keyed off a whirlwind 24 hours of global events. "Mostly we thank God for Tony's safe return".
"We have been asking for the release of these detainees for this administration for 17 months", he told reporters.
South Korea said last week that the issue of USA troops stationed in the South was unrelated to any future peace treaty with North Korea and that American forces should stay even if such an agreement is signed.
Since PUST began operating in 2010, he had made at least seven trips, usually for a month at a time, to teach worldwide finance and management to students in Pyongyang, his son Sol Kim said in an interview.
North Korea's state-run media explicitly mentioned plans for the summit for the first time.
The release appeared to signal an effort by Kim to set a more positive tone for the summit and followed his recent pledge to suspend missile tests and shut Pyongyang's nuclear bomb test site.
Clapper told CBS that he carried a short letter from Obama identifying him as the presidential envoy but made it clear that his mission was recovering the two USA citizens.
Pompeo had previously traveled to North Korea over Easter weekend, when he met with Kim.