A review by a top US Navy officer, ordered by US President Barack Obama, has found that the Guantanamo Bay detention centre meets the humane standards laid out in the Geneva Conventions.
A US official, speaking on condition of anonymity, said the review by Admiral Patrick Walsh concluded that the prison for terrorism suspects complied with Common Article Three of the conventions that governs the humane treatment of detainees.
The review was quickly criticised by the American Civil Liberties Union, which branded it a 'farce'.
In one of his first acts in office, President Obama last month ordered Guantanamo, which has been widely criticised by rights groups and foreign governments, to be closed within one year.
Mr Obama also asked Defence Secretary Robert Gates to review conditions there within 30 days to ensure detainees were being treated humanely.
Mr Gates appointed Admiral Walsh, vice chief of naval operations, to conduct the review.
Admiral Walsh was free to make recommendations and observations as well as report his conclusion, the official said, but the official declined to specify if he had done so.
The New York Times, citing two government officials who had read portions of the review, reported that Admiral Walsh made recommendations for increasing human contact between prisoners at the jail, housed at a US Naval base in Cuba.
ACLU executive director Anthony Romero said in a statement: 'The reported Pentagon review of Guantanamo appears to be nothing more than a whitewash of the Bush practices of abusive treatment and illegal detention.
'How Admiral Walsh could have completed a thorough review of the conditions of confinement and treatment of prisoners over the past seven years in the lightning speed of seventeen days belies logic and underscores what a farce this process appears to be,' he said.
Rights groups and foreign governments, including close allies of the US, have condemned Guantanamo, where many detainees have been held for years without trial, as failing to meet basic legal standards.
The Bush administration contended the jail was necessary to hold dangerous terrorism suspects and prevent them from exploiting legal protections they would enjoy in the US.
President Obama has ordered a freeze to military trials of Guantanamo prisoners while officials consider whether to change the system for trying them.
About 245 people are currently held at Guantanamo, according to the Pentagon.
