Otto Warmbier, the US student released by North Korea this week after falling into a coma while in a labor camp, has suffered "severe neurological injury," a hospital spokesman said Thursday.

The 22-year-old from Cincinnati spent more than a year in detention after being arrested for stealing a political poster from a hotel. His family have said he was "terrorized and brutalized" by Kim Jong-Un's regime.

"Otto is in stable condition but has suffered a severe neurological injury," Kelly Martin, spokeswoman for the UC Health University of Cincinnati medial center, told a news conference held jointly with the young man's father.