Vienna police said Saturday that five Afghans and an Iranian man tried to block the cell door with a locker and left a joint farewell note expressing anguish about their imminent deportations.
Officers were able to force open the cell and some 70 firefighters tackled the blaze late Friday.
Police say the men, ranging in age from 18 to 31, are in intensive care. Fourteen other people, including at least three police officers, were treated at the scene for smoke inhalation.
Austria's government, which includes the far-right Freedom Party, has pledged to step up immigration deportations since coming to power last year.