"Dennis Rodman had nothing to do with Otto", said Warmbier, referencing the high-profile trip the former National Basketball Association superstar to North Korea took the same day Otto was released.
Fred Warmbier told reporters that he received a phone call from President Trump on Wednesday night: "He just wanted to find out how Cindy [Warmbier] and I were doing, and wanted to know about Otto", Fred Warmbier said.
"I'm proud of Otto, and the courage he showed by going to North Korea", Warmbier said, "and having that adventurous side to him.so the fact that he was taken and treated this way is frightful, and it's tough to process". He was then taken by ambulance to a hospital.
The New York Times previously cited a senior US official as saying Washington had received intelligence reports Warmbier was repeatedly beaten while held captive in North Korea.
"Fred Warmbier said when his son was first detained in North Korea, he was told by the previous administration to maintain a "low profile". He was found guilty of committing a "hostile act" against the country and sentenced in March 2016 to 15 years of hard labor.
Student freed by North Korea has severe neurological injury
"We don't believe anything they say". Warmbier arrived in OH after being released by North Korea, where he was serving a 15-year prison term with hard labor for alleged anti-state acts. He also criticized the North Korean regime for its "brutal" treatment of his son.
"We went for 15 months without a word from or about Otto", Fred told the news conference.
Warmbier offered praise for the Trump administration for its work in bringing home his son.
It is unknown why North Korea released him, but Fred Warmbier claims it has nothing to do with Dennis Rodman's visit to the country this week. North Korea accuses Washington and South Korea of sending spies to overthrow its government.
The detention of Americans, often sentenced to draconian prison sentences for seemingly small offences in the totalitarian nation, has compounded tensions between Washington and Pyongyang.
He also called on North Korea to release the other Americans now imprisoned there.
This story has been corrected to show that Otto Warmbier was presented to media for his confession in North Korea in 2016, not 2015, and on February 29, not in March.