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This legal limbo is a continuing violation of human rights standards
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Amnesty International
The call comes on the first anniversary of the arrival of prisoners from Afghanistan.
About 600 suspected Taleban and al-Qaeda fighters are being held at the American base, in what Amnesty describes as a "legal black hole".
The inmates - who come from 40 different countries - have been classified by the US as unlawful combatants, not prisoners of war, and have no right to legal representation or family visits.
Suicide attempts
Since the prisoners were first taken to Guantanamo Bay, human rights activists have complained bitterly about their treatment.
Camp Delta
"This legal limbo is a continuing violation of human rights standards which the international community must not ignore," Amnesty said.
"No access to the courts, lawyers or relatives; the prospect of indefinite detention in small cells for up to 24 hours a day; the possibility of trials by executive military commissions with the power to hand down death sentences and no right of appeal: is this how the US defends human rights and the rule of law?"
Only five men - described as "not dangerous" - have been released.
All the prisoners have now been moved from the initial wire-fenced confines of Camp X Ray to the more substantial Camp Delta.
There they live in single cells, but because they can see one another are frequently shifted around, apparently to prevent cliques forming.
There have been a few, unsuccessful suicide attempts.
Appeal
The US Defence Department says it is treating the prisoners humanely and that the main reason it continues to hold them is to glean information.
It says intelligence gained from repeated interrogation has helped prevent terrorist attacks around the world.
No hint is being given as to when the prisoners will either be charged or freed.
But the BBC's Stephen Gibbs in Havana says that the intention is to hold them until the war on terrorism is over according to one official.
Lawyers for many of the prisoners - including two of the seven Britons being held - have argued that the prisoners should be charged in court or released.
But the Court of Appeals in Washington DC has yet to rule in the case.