What is Guantanamo?
Guantanamo is a high-security detention camp run by the US at its naval base in south-eastern Cuba.
America set the camp up in 2002 to hold foreign terror suspects captured during the war against the Taleban and al-Qaeda in Afghanistan.
Detainees were first kept in an improvised facility called Camp X-Ray which was replaced by a more permanent structure, Camp Delta, in 2003.
As "enemy combatants", detainees are not given the same rights as prisoners-of-war or US citizens accused of crimes.
After holding the prisoners for years without charge, the US announced it wished to try them by military tribunal.
Who are the prisoners?
The camp once held 750 inmates, believed to be mostly foreigners detained in Afghanistan on suspicion of being Islamist fighters.
Most came from mainly Muslim states, but French, Russian, British and other countries' citizens have also been held there.
Hundreds of them have been either freed or handed over to their own governments.
But the US announced the arrival of 14 new detainees in September 2006 including key figures like the suspected 9/11 mastermind, Khalid Sheikh Mohammed.
Why the outcry?
Human rights campaigners are doubtful that the prisoners will get a fair trial through the tribunal system.
The Red Cross is the only outside organisation allowed to visit the prisoners and draw up a register of them.
There are accusations of mistreatment and even torture of detainees in the camp.
United Nations investigators have called for the closure of the prison which Amnesty International campaigners have compared to a Soviet labour camp.
Even the UK, a strong American ally, has asked for the camp to close, saying it fuels Islamic radicalism.
Is the US listening?
America says prisoners are treated humanely and only a tiny number of cases of misconduct by guards have been recorded.
It argues that it does not want the same situation to continue but has no choice.
Foreign governments have been asked to take some of the prisoners.
Other prisoners face trial by the tribunals, which were only approved after heated debate in the US Congress.