An American college student serving a 15-year prison term in North Korea who was released and medically evacuated from the country on Tuesday has been in a coma for months, his parents said.

The announcement on Otto Warmbier’s release came as former NBA player Dennis Rodman was paying a return visit to Pyongyang.

Mr Rodman is one of few people to have met both North Korean leader Kim Jong Un and President Donald Trump.

Republican Senator Rob Portman says North Korea should be “universally condemned for its abhorrent behaviour”. Democratic Senator Sherrod Brown of Cleveland said the country’s “despicable actions … must be condemned.”

The parents of the 22-year-old college student said he is on a Medivac flight on his way home.

Fred and Cindy Warmbier said they have been told their son has been in a coma since March 2016, and they had learned of this only one week ago.

They said “we want the world to know how we and our son have been brutalised and terrorised by the pariah regime” in North Korea.

They also said they are grateful Mr Warmbier “will finally be with people who love him”.

The president of the University of Virginia said the school is “deeply concerned and saddened” to learn that their student is in a coma.

Dennis Rodman
Former NBA star Dennis Rodman arrives at Sunan International Airport in Pyongyang (Kim Kwang Hyon/AP)

Mr Warmbier was supposed to graduate from the university in May.

University president Teresa Sullivan said in a statement that the school is relieved to hear Mr Warmbier was released, but is concerned about his condition.

She said the university community has his family in its thoughts and prayers as he returns home.