Otto Warmbier 'unresponsive', has been in coma for a year

Otto Warmbier, an American college student imprisoned in North Korea, has been returned to the US with severe brain injuries and in a state of 'unresponsive wakefulness', doctors have said.

The 22-year-old arrived back in the US on Tuesday after being detained in the pariah state since January 2016.

But Dr Daniel Kanter, senior intensive care director at the University of Cincinnati, said Warmbier 'shows no sign of understanding language, responding to verbal commands or awareness of his surrounding'.

Kanter told a press conference: 'He has not spoken.

'He has not engaged in any purposeful movements or behaviours.'

The US student was held in North Korea since early January 2016 after being detained for trying to steal an item bearing a propaganda slogan from his Pyongyang hotel.Reuters

North Korea said Warmbier had been released on humanitarian grounds after he was sentenced to 15 years hard labour for trying to steal a propaganda sign.

North Korean officials said the American had been ill since he was arrested March 2016 from botulism – a type of poisoning caused by bacteria that can lead to paralysis – and lapsed into a coma after taking a sleeping pill.

His family said they only found out about the illness last week and refuted the North Korean's explanation. They said they wanted all to know they and their son had been 'brutalised and terrorised by the pariah regime'.

Speaking at a news conference on Thursday father Fred Warmber said he felt 'relief that Otto is now home in arms of those who love him and anger that he was so brutally treated for so long'.

The New York Times quoted a senior US official as saying Washington recently received intelligence reports that Warmbier had been repeatedly beaten in custody.

The Warbier family's local church have been praying for them ever since Otto's arrest last March.

The pastor, Eric Miller, has yet to meet Warmbier, but some members of his congregation have known him since he was a child.

'We've been praying for him, his parents, and now the people transporting him back home,' Miller said according to Cincinnati.com.

'It's overwhelming to learn that he's been in a coma for a year,' Miller added.

Of Otto's parents, Cynthia and Fred Warmbier, he said: 'I can't even begin to put myself in their shoes.'

He went on: '[Warmbier's imprisonment] has touched people's lives in our church setting. It touches a lot of people in our community in a variety of ways. I think God hears our prayers.'