WASHINGTON, July 1 : The US State Department has confirmed that four UN special rapporteurs have sought permission to visit the American prison facility at Guantanamo Bay in Cuba to investigate allegations of torture and rights violations.

The department’s spokesman Sean McCormack said they had asked the special rapporteurs to ‘specify the scope of activities in which they wish to engage at Guantanamo’.

Although he did not say when the US government received the requests, Mr McCormack said the US ambassador in Geneva, Pierre Prosper, had met the four special rapporteurs at the Commission for Human Rights meeting in April, indicating that the requests were received before the meeting.

“We receive numerous requests for a wide variety of groups and organizations for access to Guantanamo,” he added.

The US prison facility, created originally to house Haitian refugees, is now used for keeping Al Qaeda and Taliban suspects arrested in Afghanistan .

Although hundreds of prisoners have since been released, an estimated 520 detainees from over 40 countries are still there.

US and international human rights groups have accused American military authorities of subjecting the inmates to physical and mental torture.