According to the White House statement, at the direction of Trump, "Secretary of State Mike Pompeo and other representatives of the United States government traveled to Pyongyang" on May 9 to prepare for Trump's upcoming meeting with DPRK top leader Kim Jong Un.
During Pompeo's visit, the DPRK's leadership released the three U.S. detainees, said the White House.
"President Trump appreciates leader Kim Jong Un's action to release these American citizens, and views this as a positive gesture of goodwill," it said.
The White House added that the three people "appear to be in good condition and were all able to walk on the plane without assistance."
"All Americans look forward to welcoming them home and to seeing them reunited with their loved ones," it noted.
Earlier on Wednesday, Trump tweeted that Pompeo is on his way back from the DPRK with three released U.S. citizens that had been detained.
"I am pleased to inform you that Secretary of State Mike Pompeo is in the air and on his way back from" the DPRK "with the 3 wonderful gentlemen that everyone is looking so forward to meeting," Trump tweeted.
Saying that the three "seem to be in good health," Trump added they would land at Andrews Air Force Base at 2:00 a.m. EDT (0600 GMT).
Noting that he will be there to greet them, Trump hailed the news, saying "Very exciting!"
The three Korean-Americans, Kim Dong Chul, Kim Hak Song and Tony Kim, had been detained in the DPRK for one to two years.
According to media reports, Kim Dong Chul was a South Korea-born U.S. citizen and former Virginia resident. He was sentenced in April 2016 to 10 years in prison with hard labor after being convicted of espionage.
Tony Kim was detained at Pyongyang's airport in April 2017 and accused of unspecified "hostile acts" against the DPRK. He taught accounting at the Pyongyang University of Science and Technology.
Kim Hak Song, an ethnic Korean born in China, was detained in May 2017 for "hostile acts." He worked in agricultural development at an experimental farm run by the Pyongyang University of Science and Technology, which was founded in 2010 with donations from Christian groups.
The U.S. president also tweeted "Date & Place set" on Pompeo's second visit to the DPRK, referring to his anticipated summit with Kim.
He also said Pompeo had a "good meeting with Kim Jong Un."
Pompeo said Tuesday while on the plane to the DPRK that his visit was aimed to nail down a framework for the possible Trump-Kim meeting.
Pompeo said he would also talk about the release of the three men.
"We have been asking for the release of these detainees for 17 months. We'll talk about it again today," he said.
Their release would be a "great gesture" he said, adding that he hoped the DPRK would "do the right thing."
U.S. State Department spokesperson Heather Nauert said Pompeo met Kim in Pyongyang, and had a productive discussion on a range of issues, including the upcoming Trump-Kim meeting.
Nauert said Pompeo also secured the release of three U.S. citizens and is delighted to bring them home.
Trump said on May 4 that the two nations are engaged in substantial dialogues over the detainees' issue.
South Korea's Yonhap News Agency reported earlier that the three men had been relocated in a hotel near Pyongyang in April.
The summit between Trump and Kim is forecast to be held in May or early June.