Pompeo told reporters travelling with him that the three were given a quick medical exam by a physician who was accompanying the secretary and that their health "is as good as could be, given what they've been through." He said they would be transferred to another plane, apparently at Yokota Air Base in Japan, that is better equipped to handle medical needs.
Trump indicated in another tweet that Pompeo and the three Americans are expected to land at Joint Base Andrews outside Washington at 2 a.m. Thursday Eastern time, although it was not clear if they would be coming in separate planes. Trump said he would be on hand to greet them, calling it: "Very exciting!"
The three men were turned over to U.S. custody after Pompeo's meeting with Kim. According to a U.S. official who briefed reporters in Pyongyang, a North Korean official came to the Koryo Hotel to inform Pompeo that Kim had granted the three men "amnesty" on charges of espionage and hostile acts against the government - charges that U.S. officials have said were bogus.
Carl Risch, assistant secretary of state for consular affairs, and a U.S. doctor then went to another hotel to pick them up and brought them to the airport, according to a senior U.S. official present for the exchange.
"We're granting amnesty to the three detained Americans," the official quoted the North Korean emissary as telling Pompeo. "We issued the order to grant immediate amnesty to the detainees."
"You should make care that they do not make the same mistakes again," the North Korean added, according to the U.S. official. "This was a hard decision."
The two American reporters travelling with Pompeo, including one from The Washington Post, spotted the three released Americans walking from a van onto Pompeo's plane, where they were seated near medical personnel.
The release of the men coincided with additional discussions between the Trump administration and the Kim regime in preparation for the historic summit, which would be the first between a sitting U.S. president and a North Korean leader. Trump had been criticized by some foreign policy analysts for agreeing to the meeting without publicly demanding the release of the Americans as a prerequisite.
But their freedom has offered Trump new momentum in his high-stakes diplomatic gambit aimed at curtailing North Korea's nuclear weapons and ballistic missile programs. An administration official said the two sides made "substantial progress" on summit planning and agreed to meet again before the leaders' meeting.
Trump has said officials have worked out a time and location for the meeting, but he has not disclosed details. In impromptu remarks Wednesday at the White House, Trump ruled out the demilitarised zone between North and South Korea, where Kim met two weeks ago with South Korean President Moon Jae-in. He has previously said Singapore is another possible site.
"I think we have a really good shot at making it successful," Trump said of the summit, "but lots of things can happen."
Yet even as Trump projected optimism, other administration officials sounded notes of caution. Vice President Mike Pence vowed that the United States "will not let off the pressure until we achieve full denuclearisation."
The news of the Americans' release came as a huge relief to the families of the men.
"We want to thank all of those who have worked toward and contributed to his return home," said the family of Tony Kim, one of the detainees.
"We also want to thank the President for engaging directly with North Korea. Mostly, we thank God for Tony's safe return," the family said in a statement.
The three detainees were treated as "prisoners of war" and had not been seen since June, when a State Department official was allowed a brief visit with them while collecting Otto Warmbier, the detained college student who fell into a coma in North Korea and died shortly after his return to the United States.
On Friday, Trump spoke to Warmbier's family to offer emotional support. The family has sued North Korea in federal court over their son's treatment and death.
"We are happy for the hostages and their families. We miss Otto," Fred and Cindy Warmbier, Otto Warmbier's parents, said in a statement.
The longest-held prisoner was Kim Dong-chul, a 64-year-old who once lived in Fairfax, Virginia, and was arrested in October 2015. He had been based in the Chinese city of Yanji, near the border with North Korea, and travelled back and forth to the special economic zone of Rajin-Sonbong, where he managed a hotel business.
But on his last visit, he was accused of spying for South Korea's intelligence agencies, seeking to obtain details of the North's military programs and trying to spread "religious" ideas - a serious crime in the North. He was sentenced in April 2016 to 10 years in prison after a sham trial.
Then, a year ago, two men associated with the Pyongyang University of Science and Technology, or PUST, a private institution run by Korean American Christians, were detained.
Tony Kim, a 59-year-old accountant, had made at least seven trips to Pyongyang, usually for a month at a time, to teach international finance and management to students at PUST, his son Sol Kim said in an interview.
He was stopped at Pyongyang's airport in April 2017 and arrested for "committing criminal acts of hostility aimed to overturn" North Korea.
Two weeks later, Kim Hak-song, an agricultural consultant who was also living in Yanji and working at PUST, was detained. He was also arrested on suspicion of "hostile acts" against North Korea, the official Korean Central News Agency said.
Kim Dong-chul and Tony Kim were both born in South Korea, while Kim Hak-song is believed to have been born in China, although he is ethnically Korean.
South Korea's presidential Blue House welcomed the release, both for the men and their families and for the signals it sends about North Korea's sincerity.
"This decision made by North Korea will be a positive factor for the success of the North Korea-United States summit," said Blue House spokesman Yoon Young-chan.
"There's also considerable significance in the fact that all three American detainees are of Korean origin," he said.
When Pompeo touched down in Pyongyang shortly before 8 a.m. local time, he was greeted by Kim Yong Chol, a former North Korean intelligence chief, and Ri Su Yong, the influential former foreign minister. Ri is close to Kim Jong Un, having served as ambassador to Switzerland while the young leader attended school there.
Kim Yong Chol, who is in charge of relations with South Korea, and Ri, responsible for international relations, had just returned from the northeastern Chinese city of Dalian, where Kim Jong Un held talks with Chinese President Xi Jinping, their second meeting in China in 40 days.
Both also attended the inter-Korean summit with South Korean President Moon Jae-in late last month.
Pompeo told the officials over lunch that if North Korea gives up its nuclear weapons, the country can "have all the opportunities your people so richly deserve."
"For decades, we have been adversaries," Pompeo told Kim Yong Chol, a man sanctioned by the United States for his involvement with the North's nuclear program but who has emerged as one of the regime's key interlocutors to the outside world.
"Now we are hopeful that we can work together to resolve this conflict, take away threats to the world and make your country have all the opportunities your people so richly deserve," Pompeo said before lunch at the Koryo Hotel, a large, double-towered building in central Pyongyang.
"There are many challenges along the way. But you have been a great partner in working to make sure our two leaders will have a summit that is successful," the new secretary of state said.
Pompeo and Kim Yong Chol met behind closed doors at the Koryo Hotel for about an hour Wednesday morning, before a lunch complete with poached fish, duck and red wine on the 39th floor.
Kim Yong Chol was in an effusive mood, telling Pompeo and the dozen or so staffers travelling with him that this was a good time to be in Pyongyang because it was spring and because a good atmosphere had been established between North and South. This echoed remarks that both Korean leaders have made about a new spring arriving on the peninsula.
"So everything is going well in Pyongyang now," he said, adding that from now on, North Korea would be concentrating all its efforts on "the economic progress of our country."
"This is not a result of sanctions that have been imposed from outside," Kim Yong Chol told Pompeo, contradicting the administration's line that Trump's "maximum pressure" approach had brought North Korea to the negotiating table.
"I hope the United States also will be happy with our success. I have high expectations the U.S. will play a very big role in establishing peace on the Korean Peninsula," he said. Then he toasted Pompeo.
Pompeo stood and said the American delegation was "equally committed to working with you to achieve exactly" that.
