Father of recently released North Korean prisoner Otto Warmbier said the Obama administration told his family to "take a low profile."

When asked if the previous administration could have done more to secure the release of his son, Fred Warmbier responded, "I think the results speak for themselves."

The Warmbiers reached out to President Trump's administration, which took more aggressive actions to secure their son's release.

"When Otto was first taken, we were advised by the past administration to take a low profile, while they worked to obtain his release. We did so without resolve," Warmbier said. "Earlier this year, Cindy and I decided the time for strategic patience was over, and we made a few media appearances and traveled to Washington to meet with ambassador Joe Yun at the state department."

Otto Warmbier, 22, was sentenced to 15 years of hard labor for ‘hostile acts' against North Korea after he allegedly took down a poster. He returned to the United States on Tuesday after 18 months of imprisonment, but is in bad medical condition after being left in a coma for most of that time.

He suffered a severe brain injury and has been in a coma for about a year, his father said.