Friends of a Sheffield student who fled Isis are rallying round in a bid to prevent his deportation.
More than 2,600 people have signed a petition calling for Ahmed Sedeeq, aged 30, to be given a reprieve.
Ahmed, from the city of Mosul in northern Iraq, is studying for a PhD in computer science at Sheffield University, but supporters say he has been held at Morton Hall immigration centre, Lincolnshire, since Monday and could be deported because of a visa dispute.
His friend Alvin Pastore, who organised the online petition, said Ahmed first came to the UK in 2011 to take a masters in Advanced Software Engineering at the university, returning to Mosul afterwards.
He then gained a PhD position at Sheffield's department of computer science, and came back to the UK again in 2013 after applying for a student visa. He applied for asylum in the UK in 2014, when Jihadist group Isis declared Mosul its capital.
Alvin, who studied alongside Ahmed, said his case was rejected multiple times but he eventually obtained a shortened student visa, which he exceeded mistakenly.
"He has been informed that he is at risk of being sent back to Iraq at any time," said Alvin.
"He is under a lot of pressure and his mental well being is currently bad enough for us to be deeply worried about him."
The petition's response reflected how well-liked Ahmed was, Alvin said.
"Ahmed is a really nice and humble person, very selfless, passionate about computer science, and his life is genuinely in danger if he is sent back to Iraq.
"He's very openly an atheist, and has spoken out against radical Islamism multiple times, which means going back to Iraq would be a threat to his life.
"He's integrated very well with the western culture and he should have a chance of finishing his PhD studies here in the UK, for which he was self-funded and has already spent £57,000 on tuition fees."
A Home Office spokesman said: “All applications are considered on their individual merits and in accordance with the immigration rules.
"When someone has no leave to remain in the UK, we expect them to leave the country voluntarily. Where they do not, we will seek to enforce their departure.”
The university said it was aware of Ahmed's case and was 'committed to ensuring universities remain diverse, inclusive communities of international scholarships open to students and staff from across the world.'
Visit www.change.org/p/home-office-and-amber-rudd-please-let-ahmed-finish-his-phd-in-the-uk to see the petition.