Hearings at Guantanamo were suspended by President Obama
US President Barack Obama ordered the closure of the Guantanamo Bay detention centre in Cuba by 2 January 2010.
But after initially suspending the system of military tribunals used by the Bush administration to try some terror suspects held there, Mr Obama has decided to retain the system, with slightly modified rules.
When announcing the camp's closure, Mr Obama also outlawed the use of torture by US interrogators and ordered the closure of all secret CIA detention facilities around the world.
What is President Obama doing about Guantanamo?
On 22 January 2009, two days after taking office, he declared that the detention camp at Guantanamo Bay "shall be closed as soon as practicable, and no later than one year from the date of this order."
A review of each prisoner's status is being carried out and a high-level task force will decide what will happen to them. The president asked that tribunals already underway be suspended for 120 days, while he reached a decision about whether to stop them permanently and try suspects in ordinary courts, or retain them in some modified form.
On 15 May 2009, he announced that he would retain the tribunal system.
Why were the Bush administration's military tribunals controversial?
They were set up in 2006 to try terror suspects under separate rules from regular civilian or military courts. They were made up of between five and 12 US military officers. A conviction required two-thirds of the commission members to be in favour. For a death sentence, all 12 commission members had to agree.
Hearsay evidence and evidence obtained under coercion was allowed if it were deemed to have "probative value". The interrogation technique of "waterboarding" or simulated drowning was not classified as torture by the Bush administration.
What rule changes has Mr Obama proposed for the military tribunals?
In the revised tribunals:
- Statements that have been obtained from detainees using "cruel, inhuman and degrading interrogation methods" will no longer be admitted as evidence at trial;
- The use of hearsay evidence will be limited, so that the burden will no longer be on the party who objects to hearsay to disprove its reliability;
- The accused will have "greater latitude" in selecting their counsel;
- "Basic protections" will be provided for those who refuse to testify; and
- Tribunal judges may "establish the jurisdiction of their own courts".
So will all Guantanamo detainees be tried using the revised tribunal system?
No. While some will go through the revised military tribunals, others may be tried in regular federal courts. It is thought about 50 or so might face trial or military tribunal - so far only 21 have actually been charged.
Others will be freed. Some 60 detainees have already been cleared for release. They will either be sent to their home countries, or - if their home countries are deemed to have a poor human rights record - to friendly third countries, or possibly even to the US itself.
Where might they be sent?
Several European nations, including Portugal, France, Ireland, Sweden and Germany, have said they recognise the need to take some men who cannot return to their home countries because of the risk of mistreatment.
Albania is one of the only countries to have so far accepted Guantanamo detainees, taking in five members of China's Uighur ethnic minority on humanitarian grounds in 2006.
There has been speculation that some other Uighur detainees could be released in the US.
What about those who are neither tried nor released?
There are a number of detainees who are in limbo, with not enough presentable evidence against them nor confidence that they would not take up violence if they were released.
Defence Secretary Robert Gates has said that between 50 and 100 detainees cannot be tried or released.
What about the alleged leaders of the 9/11 attacks?
Their trial was one of those suspended. However, the alleged mastermind, Khalid Sheikh Mohammed, told the judge at the suspension hearing that he wanted the tribunal to continue. He has previously said that he wants to be a "martyr" there.
Following President Obama's decision to retain military commissions, their trial will at some point continue.
Where would those not released be taken?
They would be transferred to facilities on the US mainland. Three military prisons - at Fort Leavenworth in Kansas, Camp Pendleton in California, and Charleston in South Carolina - are among some of the possible locations, according to administration officials.
There could well be local opposition wherever the detainees are transferred. Some critics have said dangerous suspects could be brought to the US and it is possible they could be freed in court challenges.
What about the ban on torture?
This order fulfils another of President Obama's promises. Under President Bush, the US military were confined in their interrogation techniques to those described in the Army Field Manual. This bans ill-treatment but allows techniques such as tricks and ruses. But the CIA was allowed to continue the practice of waterboarding, in which a prisoner is held down and water poured onto his face in a simulation of drowning.
The CIA will now have to follow the Army Field Manual and all prisoners will have to be treated in accordance with Common Article 3 of the Geneva Conventions which prohibits cruel, humiliating or degrading treatment.
But doesn't the order allow the US government to review interrogation techniques?
Yes. A study group will examine whether the techniques allowed in the Army Field Manual, when used by agencies outside the military (i.e. the CIA mainly), "provide an appropriate means of acquiring the intelligence necessary to protect the Nation." Human rights groups will be watching carefully for the results of this study.
And the closure of the secret CIA centres?
President Obama ordered the closure of "any" such secret prisons, thereby avoiding an admission about how many, if any, currently exist and how many there were in the past.
Is there now a ban on secret renditions?
President Obama has ordered a review of such "transfers", as the order calls them. These are secret flights taking prisoners from one country to another. The order says that any transfers must be consistent with US obligations and must not result in individuals facing torture.
How have the reports of Guantanamo's planned closure been received?
Some relatives of the 11 September victims are opposed to the camp's closure, believing that it is a secure location to try terrorism suspects.
Human rights groups have broadly welcomed the move. However, some activists and lawyers have expressed concern that it could take as long as a year to close Guantanamo.
Campaigners are also disappointed with Mr Obama's decision to continue using military tribunals to try detainees.
Has anyone been convicted by the military tribunals?
In March 2007 an Australian, David Hicks, pleaded guilty to helping the Taleban and was sent back home to serve a nine-month sentence.
In August 2008, a military jury convicted Osama Bin Laden's former driver, Salim Hamdan, of supporting terrorism. He was sentenced to 66 months. As he had spent time in pre-trial detention, his sentence was completed in November 2008 and he was returned to his home country of Yemen.
Ali al-Bahlul was sentenced to life imprisonment in November 2008. He was said to be al Qaeda's propaganda chief who made videos and personally recorded the final statements of two of the 9/11 hijackers.