JOINT BASE ANDREWS - President Trump and first lady Melania arrived early Thursday morning to greet three Americans as they flew into Joint Base Andrews, outside the U.S. capital, less than 24 hours after they were released by North Korea.

The three men, Kim Dong Chul, Kim Hak Song and Tony Kim, were released during a visit on Tuesday by U.S. Secretary of State Mike Pompeo, and were in the air less than one hour after being released in North Korea's capital city, Pyongyang.  

Pompeo and the former detainees arrived on two separate planes. Secretary Pompeo touched down first, and the plane carrying the three former detainees arrived about half an hour later at the U.S. military base in suburban Maryland. The plane pulled to a rest in front of a giant U.S. flag, stretched between two cranes on the tarmac. Mr. Trump boarded the plane with the first lady and then emerged at the top of the stairs with the three men to wave, and then walk down onto the tarmac together.

Pompeo greeted them at the bottom of the stairs and was hugged by one of the former prisoners. The three men appeared healthy as they walked toward waiting reporters. President Trump made brief remarks, saying "his proudest achievement will be -- this is a part of it -- but my proudest achievement will be when we denuclearize" North Korea.

Mr. Trump said he "very much appreciated" that Kim Jong Un had released the prisoners ahead of the two leaders' looming meeting. 

"This is a special night for these three really great people," Mr. Trump said, adding, "congratulations on being in this country."

Kim Dong Chul, a day after his release, said through a translator as he stood next to Mr. Trump that being home was "like a dream, and we're very, very happy." Asked how he was treated in North Korean custody, Kim only said, "in many different ways." 

President Trump also "paid his respects" to the family of Otto Warmbier as he stood with the freed men. Warmbier was an American student who died shortly after his return to the U.S. last year following his release by North Korea. Warmbier was flown home with severe brain damage, and his parents have sued North Korea over his death. 

The three Americans formerly held hostage in North Korea gesture next to U.S.President Donald Trump and Secretary of State Mike Pompeo, upon their arrival at Joint Base Andrews 
While the three men are walking on their own strength and appear healthy, they were transported immediately to the military's Walter Reed Medical Center in Washington for thorough health checks. 

North Korea released the prisoners as Pompeo visited the country to nail down the details of a looming meeting between Kim Jong Un and President Trump. U.S. officials are now planning for the summit to happen in Singapore, sources told CBS News on Wednesday.

The White House has lauded the Kim regime for releasing the three men, saying it helped to create a positive atmosphere for the upcoming summit. 

The Associated Press contributed to this report.