An American student being held prisoner in North Korea has been medically evacuated from the country in a coma, his family have said.

Otto Warmbier, 22, has been detained by the North Koreans for a year and a half.

He has been in a coma for more than a year, his family said, saying he had fallen ill shortly after his last public appearance during his trial in Pyongyang in March, 2016.

“Our son is coming home,” said Fred Warmbier, speaking to The Washington Post.

“At the moment, we’re just treating this like he’s been in an accident. We get to see our son Otto tonight.”

The Warmbiers were told that he had come down with a case of botulism soon after his trial – which lasted only one hour – and had been given a sleeping pill, from which he never woke up.

Rex Tillerson, the secretary of state, said that Mr Warmbier was on his way back to his home of Cincinnati, but did not discuss his medical condition.

"We have no comment on his medical condition, out of respect to his family," said Mr Tillerson.

The University of Virgina student was detained while "carrying out anti-DPRK hostile activities," North Korea's state media declared on January 22, 2016, using the country's official acronym.