Snipped from the New York Times:
Lawyers representing detainees at Guantánamo Bay, Cuba, say that there still may be as many as six prisoners who were captured before their 18th birthday and that the military has sought to conceal the precise number of juveniles at the prison camp.
One lawyer said that his client, a Saudi of Chadian descent, was not yet 15 when he was captured and has told him that he was beaten regularly in his early days at Guantánamo, hanged by his wrists for hours at a time and that an interrogator pressed a burning cigarette into his arm.
Link. In related news: Time report fuels Guantanamo criticism, and here is the link to the Time article referenced (sub required)