The US defence department has announced a new investigation into allegations of prisoner abuse at the Guantanamo Bay detention centre.
The abuse allegations date back several years
Documents published last month suggest FBI officials expressed concerns over the mistreatment of prisoners at Guantanamo Bay as far back as 2002.
There have been numerous allegations of abuse and torture at the centre.
The internal probe has been ordered by the head of the US Southern Command, which covers Guantanamo Bay.
The detention centre at the US base in Cuba currently holds almost 550 detainees from around 40 countries, mostly captives from the war in Afghanistan.
FBI memos detailing abuses - some dated after the Abu Ghraib scandal surfaced last May - were obtained by the American Civil Liberties Union under the Freedom of Information Act.
One agent described seeing prisoners shackled, hand and foot, in a foetal position for up to 24 hours at a time, and left to defecate on themselves.
Another, sent to FBI Director Robert Mueller, described strangulation, beatings and the placing of lit cigarettes into detainees' ears.
Allegations of abuse in Iraq rocked the US military
Some of the memos were written in response to a request by a senior FBI official that agents tell him if they had witnessed "aggressive treatment", in the wake of the Abu Ghraib abuse scandal in Iraq.
The Pentagon says prisoners are treated humanely, but has promised to investigate all credible allegations of abuse.
The UK-based human rights group Amnesty International has accused the US government of tolerating mistreatment.
The new investigation has been ordered by General Bantz Craddock, the head of US southern command which has responsibility for Guantanamo Bay.
The inquiry is to be led by US Army Brigadier General John Forlow.
There have been eight major official investigations into allegations of prisoner abuse in Iraq, Afghanistan and Guantanamo Bay.
A further three are outstanding.