Updated

The United States should shut down the prison for terror suspects at Guantanamo Bay and either release all detainees being held there or bring them to trial, the United Nations said in a report released Thursday.

The report, summarizing an investigation by five U.N. experts, called on the U.S. government "to close down the Guantanamo Bay detention center and to refrain from any practice amounting to torture or cruel, inhuman or degrading treatment."

The report's findings were based on interviews with former detainees, public documents, media reports, lawyers and a questionnaire filled out by the U.S. government.

The United States is holding about 500 men at the U.S. naval base on the southeastern tip of Cuba. The detainees are accused of having links to Afghanistan's ousted Taliban regime or the Al Qaeda terror group, though only 10 have been charged since the detention camp opened in January 2001.

In a response included at the end of the report, the U.S. ambassador to the U.N. offices in Geneva said investigators had taken little account of evidence against the abuse allegations provided by the United States and rejected an invitation to visit Guantanamo.

"It is particularly unfortunate that the special rapporteurs rejected the invitation and that their unedited report does not reflect the direct, personal knowledge that this visit would have provided," ambassador Kevin Moley wrote.

The five U.N. experts had sought invitations from the United States to visit Guantanamo since 2002. Three were invited last year, but refused to go in November after being told they could not interview detainees.

The International Committee of the Red Cross has been allowed to visit Guantanamo's detainees, but the organization keeps its findings confidential, reporting them solely to U.S. authorities. Some reports have been leaked by what the organization calls third parties.

Although the investigators did not visit Guantanamo, they said photographic evidence and the testimonies of former prisoners showed detainees were shackled, chained, hooded and forced to wear earphones and goggles. They said prisoners were beaten if they resisted.

"Such treatment amounts to torture," the report said.

Some interrogation techniques — particularly the use of dogs, exposure to extreme temperatures, sleep deprivation for several consecutive days and prolonged isolation — caused extreme suffering, the report said.

It also concluded that the particular status of Guantanamo Bay under the international lease agreement between the United States and Cuba did not limit Washington's obligations under international human rights law toward those detained there.

Many of the allegations have been made before, but the document represented the first inquiry launched by the 53-nation U.N. Human Rights Commission, the world body's top rights watchdog.

The five investigators, who come from Argentina, Austria, New Zealand, Algeria and Pakistan, were appointed by the commission to the three-year project. They worked independently and received no payment, though the U.N. covered expenses.

The U.S., which is a member of the commission, has criticized the body itself for including members with poor human rights records.