United States student Otto Warmbier has been freed from jail in North Korea, 13 months after being sentenced to 15 years of hard labour.
Tillerson said the State Department secured Warmbier's release at the direction of President Trump.
Former NBA star Dennis Rodman said on Tuesday he was about to visit North Korea as a private citizen.
'We've been praying for him, his parents, and now the people transporting him back home, ' Miller said after Warmbier's release.
Our sympathies go out to Otto Warmbier and his family. "North Korea is persecuting their savior, a person who came to help them".
"We're absolutely thrilled. There are many happy people tonight in Wyoming", Wyoming City Council member Jenni McCauley said.
It was not immediately clear if Rodman's visit to North Korea was purely coincidental with Warmbier's release.
Earlier Tuesday, Fred Warmbier told The Cincinnati Enquirer said the family would hold a news conference Wednesday in Cincinnati, with the details yet to be finalized. PotCoin stock soared almost 100 percent after news and photos of Rodman were published upon his arrival in North Korea.
Currently, a total of six South Koreans are detained in North Korea, including several religious missionaries accused of treason or espionage.
"Dennis Rodman had nothing to do with the release of Mr. Warmbier", said Heather Nauert, a State Department spokeswoman.
Yun's visit came amid heightened tensions over North Korea's defiant pursuit of advanced military technologies, but USA media reports said, his mission, directly ordered by Trump, was centered on the 22-year-old student's immediate release on humanitarian grounds.
Secretary of State Rex Tillerson confirmed the release and said Washington remained in talks with the isolated regime "regarding three other U.S. citizens reported detained". "Since we also have our citizens detained in the North. we are putting pressure on the North to free them through various channels", he said, vowing "utmost efforts".
After a short trial on 16 March, Mr Warmbier was given a 15-year prison sentence for crimes against the state.
In the 1990s he visited at President Clinton's request to secure the release of the pilot of a US helicopter downed after unintentionally straying across the DMZ during a routine training mission (a second pilot was killed); and to bring home an American man accused of espionage after swimming across a river on the North Korea-China border. "This is wrong", David Lee, one of the men who said he studied with Kim, told CNN.
Richardson, a former Democratic congressman, U.N. Ambassador, U.S. energy secretary and ex-governor of New Mexico, welcomed Warmbier's release but said "we are deeply concerned regarding his health".
The announcement comes as former National Basketball Association superstar Dennis Rodman makes a return visit to the hermit kingdom where he has regularly enjoyed access to the country's top leadership, including Supreme Leader Kim Jong-un. They said they were told their son has been in a coma since his trial - when he was last seen in public - and they had learned of this only one week ago.
Americans are regarded as enemies in North Korea because the two countries never signed a peace treaty at the end of the 1950-53 Korean War.
If nothing else, the confluence of these two events highlights the enduring strangeness of North Korea as an actor on the worldwide stage.
The 56-year-old NBA Hall of Famer, who was heavily criticized for failing to raise the plight of a jailed United States missionary on a previous trip, said discussing detained USA citizens was "not my objective right now".