Former US military prisoners in Afghanistan have said that they were abused in a secret prison on Bagram airbase as recently as this year, raising fears that detainee mistreatment has continued despite an overhaul of US detention operations in the country. The abuse - which includes exposure to extreme temperatures, lack of adequate food and bedding, lack of natural light and interference with religious duties - is alleged to have occurred at a secret "screening" facility on the military base north of Kabul.