A new report from a U.S. 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 U.S. 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 on Thursday denied it ran any such hidden jails