Bomb attacks by insurgents are still a danger in Iraq
The Home Office says there is "no suggestion" that nearly 50 asylum seekers have gone on hunger strike at a detention centre in West Sussex.
A group called the International Federation of Iraqi Refugees says the men have not eaten since Sunday and will continue until they are released.
Most of them were on board a deportation flight to Baghdad last week that Iraqi authorities turned back.
The Home Office said the Brook House centre was "operating normally".
In a statement, a spokesman said: "There is no suggestion of this protest taking place at Brook House."
The Home Office has said previously that the reason the detainees were sent back to the UK was "a matter for the Iraqi government".
The Home Office had planned to deport about 40 failed Iraqi asylum seekers to Baghdad last week, but Iraqi authorities turned most of them away.
It was suggested in reports that Iraq's authorities were not happy they could confirm the identities - or even nationalities - of the deportees.
The men were flown back to Gatwick airport and detained at Brook House.
In a statement released by the International Federation of Iraqi Refugees (IFIR), the strikers said: "We have been in detention centres for months and years and our cases have not been handled professionally.
"We are all locked up in detention, which is exactly like a prison, but most of us have never committed any crime whatsoever.
"We are going on hunger strike until they release us.
"Most of us are being falsely removed to countries like Afghanistan and Iraq, which are clearly war zones.
"Most of us have families in the UK. What are we supposed to do? Leave them behind or take them with us right into the middle of a war zone to be killed?"
Asylum seekers from Afghanistan, Algeria, Nigeria and Jamaica have also gone on hunger strike, IFIR said.
The UK Border Agency has pledged to "iron out" any problems to allow another flight to leave soon for Baghdad, but it will not say exactly when.
MPs have signed an early day motion from John McDonnell, MP for Hayes and Harlington in west London, calling for the flights to be halted.