FILE - This 2016 file photo provided by the family of Tony Kim, shows him in California. Kim and two other Americans detained in North Korea for more than a year are on their way back to the U.S. with Secretary of State Mike Pompeo, President Donald Trump announced Wednesday, May 9, 2018, in the latest sign of improving relations between the two longtime adversary nations. (Tony Kim family via AP, File)
FILE - This 2016 file photo provided by the family of Tony Kim, shows him in California. Kim and two other Americans detained in North Korea for more than a year are on their way back to the U.S. with Secretary of State Mike Pompeo, President Donald Trump announced Wednesday, May 9, 2018, in the latest sign of improving relations between the two longtime adversary nations. (Tony Kim family via AP, File)

WASHINGTON — Freed after more than a year in prison, three Americans flew homeward from North Korea late Tuesday toward a big middle-of-the-night celebration featuring President Donald Trump — the latest sign of improving relations between longtime adversaries in the buildup to a historic summit between Trump and North Korea’s Kim Jong Un.

Trump promised “quite a scene” at Joint Base Andrews outside Washington for the detainees, who were released as Secretary of State Mike Pompeo visited North Korea on Wednesday to finalize plans for the summit. Singapore was the likely site, late this month or in early June, for Trump’s most ambitious foreign police effort yet.

Shortly after they touched down on American soil in Alaska, the State Department released a statement from the freed men.

“We would like to express our deep appreciation to the United States government, President Trump, Secretary Pompeo, and the people of the United States for bringing us home,” they said. “We thank God, and all our families and friends who prayed for us and for our return. God Bless America, the greatest nation in the world.”

The men had boarded Pompeo’s plane out of North Korea without assistance and then transferred in Japan to a separate aircraft with more extensive medical facilities. They are expected to arrive at Joint Base Andrews outside Washington in the wee hours of Thursday morning.

Trump made a point of publicly thanking North Korea’s leader for the prisoners’ release — “I appreciate Kim Jong Un doing this” — and hailed it as a sign of cooling tensions and growing opportunity on the Korean peninsula. Kim decided to grant amnesty to the three Americans at the “official suggestion” of the U.S. president, said North Korea’s official news agency, KCNA.

North Korea had accused Kim Dong Chul, Kim Hak Song and Tony Kim, all Korean-Americans, of anti-state activities. Their arrests were widely seen as politically motivated and had compounded the dire state of relations over the isolated nation’s nuclear weapons.

Trump entered office as an emboldened North Korea developed new generations of nuclear weapons and ballistic missiles capable of hitting the continental U.S. Those advances were the subject of President Barack Obama’s warning shortly before Trump took office, and this is a crisis he’s convinced his negotiating skills can resolve.

Crediting himself for recent progress, Trump has pointed to Kim’s willingness to come to the negotiating table as validating U.S. moves to tighten sanctions — branded “maximum pressure” by the president. The wee-hours ceremony Thursday was to be an early celebration for an issue that has already put the prospect of a Nobel Peace Prize on Trump’s mind.

“Everyone thinks so, but I would never say it,” he said Wednesday when asked if the award was deserved.

The release capped a dramatic day of diplomacy in Pyongyang. After Pompeo’s 90-minute meeting with Kim Jong Un, he gave reporters a fingers-crossed sign when asked about the prisoners as he returned to his hotel. It was only after a North Korean emissary arrived a bit later to inform him that the release was confirmed.

The three had been held for periods ranging from one and two years. They were the latest in a series of Americans who have been detained by North Korea in recent years for seemingly small offenses and typically freed when senior U.S. officials or statesmen personally visited to bail them out.