KABUL : A new report from a US foundation details allegations of detainee abuse as recently as this year from Afghans who say they were held at a secret jail inside the main American military base in Afghanistan. The US military has long operated a facility to detain those captured in Afghan operations, first inside Bagram Air Field and now right next door. But some former detainees have alleged for years they were held at a smaller, more isolated location at the base, dubbed the “Black Jail.” The military Thursday denied it ran any such hidden jails and said that all detention facilities are held to the same strict standards of conduct, consistent with US law, Defense Department policy and Common Article III of the Geneva Conventions. The report released Thursday by the New York-based Open Society Foundations, a grant-making and policy organization founded by liberal billionaire George Soros, lists a host of accusations of mistreatment at the alleged site. Former detainees said they were exposed to excessive cold and light, not given enough food or blankets, deprived of sleep, stripped naked for medical exams and kept from practicing their religion. If the allegations prove true, they could tarnish the push for detention reform by US President Barack Obama. His administration has ushered in improvements in detainee conditions in Afghanistan although it has been unable to deliver on a campaign promise to close the US military prison at Guantanamo Bay in Cuba. Among changes made in the past two years in Afghanistan: reporters have been allowed to tour the main facility outside Bagram and sit in on the review boards used by US authorities to determine if a detainee remains a threat. The majority of detainees are now also given access to Afghan lawyers and their case is heard in an Afghan court held at the center. The report is based on interviews from 18 detainees who say they were held at a facility matching the description of the alleged Black Jail - half of them during 2009 and 2010, after the military had implemented its reforms. “Given the consistency of the accounts, the Open Society Foundations believes these are genuine areas of concern, and not outliers, that run counter to US rules on detainee treatment,” the report says.