Lawyers representing hunger-striking detainees at America’s controversial Guantánamo Bay prison have warned they fear some of the protesters could soon die in the ongoing protest.

The news comes as fresh details emerge about conditions at the camp from lawyers visiting clients, letters being written by inmates and phone calls from inside the prison.

They describe dramatic weight loss among many of the hunger strikers, force-feeding, putting protesters in isolation and at least one suicide attempt – though that has been denied by military authorities.

In a letter written by Djamel Ameziane – an Algerian prisoner who has been cleared for release after 11 years of being detained without trial – guards were accused of pressuring prisoners to break the strike. “They are trying to deprive us of everything they can,” he wrote in the letter, extracts of which were seen by the Guardian. Ameziane added that inmates were being disturbed during prayers and that the temperature in cell blocks had been lowered to make inmates less comfortable.