Screenshot/ABC News

Otto Warmbier's father, Fred Warmbier, spoke publicly on Thursday for the first time since Otto was released from North Korea earlier this week. Warmbier, 22, was sentenced to 15 years hard labor in 2015, when he was 21, after he stole a propaganda sign from his hotel room. Warmbier's release was announced on Tuesday by Secretary of State Rex Tillerson. Pyongyang claims they released Warmbier on "humanitarian grounds"; he has allegedly been in a coma since shortly after he was sentenced.

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. "It was a really nice conversation. It was kind. It was, 'Are you taking care of yourself?' And, 'We worked hard, and I'm sorry this is the outcome.'"

Fred Warmbier added: "To be honest with you, I had avoided conversations with [Trump]. Because, to what end? I'm dealing with my son, this is about Otto. But I did take the call and it was gracious, it was nice, and it felt good. And I thank him for that."

Fred Warmbier also criticized the Obama administration, giving credit to President Trump for returning Otto to the United States. "When Otto was first taken, we were advised by the past administration to take a low profile while they worked to obtain his release," Warmbier said. "We did so without result. Earlier this year, Cindy and I decided the time for strategic patience was over. … It is my understanding that [Special Representative for North Korea Policy Joseph Y. Yun] and his team, at the direction of the president, aggressively pursued resolution of the situation."

When asked directly if he believed Obama could have done more to help Otto Warmbier, Fred Warmbier said: "I think the results speak for themselves."