WASHINGTON - The notorious military prison at Guantanamo Bay jail has once against been at the centre of a furor this week after five Taliban prisoners were exchanged for a US soldier held in Afghanistan.
The five senior Taliban figures exchanged for Sergeant Bowe Bergdahl were not among the group of prisoners at the base in southern Cuba who had already been approved for release.
US lawmakers were also angered that they were not given the mandatory 30-days notification of the releases, as the administration said it had to act quickly because Bergdahl's health was failing.
A senior administration official on Thursday said: "There are a significant number of transfers in the pipeline at various stages and I think you're going to be seeing substantial progress this year."
Here is a fact file about the Guantanamo Bay detention centre:
It was opened in January 2002 on a US military base on a coastal spit of land in southern Cuba leased from Havana under a treaty dating back to 1903. It was set up in the wake of the 9/11 attacks under the administration of then president George W. Bush to deal with prisoners who became termed "enemy combatants."
But it quickly became a hated symbol of the so-called "war on terror" with orange jumpsuit-clad prisoners photographed shackled and handcuffed in open cages. The cages were later closed.
US President Barack Obama has repeatedly vowed to close the jail, but his attempts have been partly hampered by Congress which refuses to allow any of the inmates to transferred from the prison, dubbed Gitmo, to US soil.
There are currently 149 prisoners in the jail, out of a total of 779 who have been held there over the years. Of the 149, some 78 have been approved for release without charge because they are not considered "a significant security threat to the United States." These include among others 58 Yemenis, five Tunisians, four Afghans and four Syrians.
A second group of 71 remaining prisoners includes 10 who have already been charged and face trial by a special US military commission. A further 23 have been referred for prosecution, while 38 are eligible to have their cases reviewed. The five Taliban who were released last week came from among this group.