KABUL, Afghanistan, May 11 (UPI) -- The Red Cross says a U.S. air base in Afghanistan has established a separate facility from its main prison that is being used for detainees.

The International Committee for the Red Cross says since August 2009 U.S. authorities have been providing the names of prisoners in a separate facility at Bagram Air Base, the BBC reports.

Nine former prisoners have told the BBC they were held in a separate building and subjected to abuse.

They told of being held in isolation in cold cells where lights are on day and night and U.S. military personnel prevented them from sleeping.

Vice Adm. Robert Harward, head of U.S. detention in Afghanistan, denies the existence of a separate facility at Bagram.

The U.S. military has agreed to investigate allegations of abuse that were made to the BBC.