With the tense relationship between the United States and North Korea, State Department spokeswoman Heather Nauert strongly advises against traveling to the East Asian country.
He was visiting North Korea with a tour group.
"They may put some more pressure on the Chinese, but the testimony of [Defense Secretary Jim] Mattis suggests the administration has made the threat of North Korea its number one priority", he said.
"State Security concealed whatever it was and have been concealing it for some time", Madden said, citing North Korean sources.
"The fact that he was taken and treated this way is disgusting, and tough to process", Fred Warmbier said.
"How safe is it?"
(AP Photo/John Minchillo). Friends and relatives gather to listen as Fred Warmbier, father of Otto Warmbier, a University of Virginia undergraduate student who was imprisoned in North Korea in March 2016, as he speaks during a news conference, Thursday.
"Dennis Rodman had nothing to do with Otto", he said. "We have never felt suspicious or threatened at any time". The Republican congressman says he wants to make sure the Treasury Department does not issue licenses for tourism to North Korea.
Yun boarded a private aircraft along with two doctors and arrived Monday in Pyongyang, where they were met by North Korean officials and saw Warmbier in a hospital.
State media in North Korea claims Warmbier was released for "humanitarian reasons".
Warmbier was sentenced to serve 15 years of hard labor after he confessed to stealing a political poster from his hotel during a trip to the country.
Kim Dong-chul was arrested on accusations of espionage shortly after Warmbier's sentencing and has been held ever since.
The Obama administration had encouraged family to keep a low profile while it negotiated with the North Korean government to secure Warmbier's return. Company founder Gareth Johnson told VICE in an interview later that year that he could not discuss Warmbier's situation out of respect for his family.
"We relied on this false premise that they would treat Otto fairly and let him go", Warmbier said. "We are continuing to work closely with relevant authorities to ensure a speedy and satisfactory outcome for Mr Warmbier". "In fact, we don't target or mention Americans specifically in any of our advertising", he added.
Young Pioneers, whose website boasts of providing "budget travel to destinations your mother would rather you stay away from", is among the most popular choice of tour operators among young Westerners.
The elder Warmbier said he didn't believe North Korea's explanation that the coma resulted from botulism and a sleeping pill.
The charge against Otto, according to North Korean news agency, was "perpetrating a hostile act against" the Democratic People's Republic of Korea - the official name for the reclusive Communist nation. Mitchell seemed to be shifting the blame to longstanding USA policy rather than the Obama administration's inability to get results.
North Korea is inviting Westerners to visit the isolated country to boost domestic tourism just days after sending one home with severe brain damage. But U.S. citizens are not banned from travel to either place.