The 54-page 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."
But the U.S. ambassador to U.N. offices in Geneva, Kevin Moley, responded that the investigation had taken little account of evidence provided by the United States, and that the five U.N. experts 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," Moley wrote in a response that was included at the end of the report.
was leaked earlier this week before it included U.S. comment.
The U.S. is holding about 490 men at the U.S. military detention center 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 a handful have been charged since the mission opened in January 2001.
The five U.N. experts who authored the report had sought invitations from the United States to visit Guantanamo Bay since 2002. Three were invited last year, but refused in November after being told they could not interview detainees.
Only 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 the detaining power. Some reports have been leaked by what the organization calls third parties.
The U.N. report's findings, which were being made public, were based on interviews with former detainees, public documents, media reports, lawyers and a questionnaire filled out by the U.S. government.
The treatment of detainees during transport and the use of violence when they resisted amounted to torture, the U.N. report said.