"Unfortunately, the awful torturous mistreatment our son received at the hands of the North Koreans ensured that no other outcome was possible beyond the sad one we experienced today," the family said in a statement following Warmbier's death at 2:20 p.m. EDT (1820 GMT) at the University of Cincinnati Medical Center.
His family has said that Warmbier, 22, had lapsed into a coma in March 2016, shortly after he was sentenced to 15 years of hard labor in North Korea.
He was arrested, according to North Korean media, for trying to steal an item bearing a propaganda slogan.
North Korea released Warmbier last week, saying he was being freed "on humanitarian grounds."
The University of Virginia student's father, Fred Warmbier, said last week that his son had been "brutalized and terrorized by the Pyongyang government and that the family disbelieved North Korea's story that his son had fallen into a coma after contracting botulism and being given a sleeping pill.
Doctors who examined Otto Warmbier after his release said there was no sign of botulism in his system.
Warmbier was freed after the U.S. State Department's special envoy on North Korea, Joseph Yun, traveled to Pyongyang and demanded the student's release on humanitarian grounds, capping a flurry of secret diplomatic contacts, a U.S. official said last week.
Tensions between the United States and North Korea have been heightened by dozens of North Korean missile launches and two nuclear bomb tests since the beginning of last year. Pyongyang has also vowed to develop a nuclear-tipped intercontinental ballistic missile capable of hitting the U.S. mainland.
Susan Thornton, the U.S. acting assistant secretary of state for East Asia, said earlier on Monday that the United States was concerned for the welfare of the three other U.S. citizens still held in North Korea - Korean-Americans Tony Kim, Kim Dong Chul and Kim Hak Song.
Thumbnail Credit: REUTERS, Kyodo