GENEVA – Two decades after the first detainees arrived at Guantanamo Bay, a group of UN experts on Monday urged Washington to finally close the site of “unrelenting human rights violations”.

More than a dozen independent UN rights experts voiced outrage that the military prison in Cuba created after the September 2001 attacks to house detainees in the US “war on terror” was still operating.

On the 20th anniversary of the first arrivals at the detention centre, they described it as a site of “unparallelled notoriety” and a “stain” on Washington’s stated commitment to the rule of law.

“Twenty years of practising arbitrary detention without trial accompanied by torture or ill treatment is simply unacceptable for any government, particularly a government which has a stated claim to protecting human rights,” they said in a statement.

Two UN working groups, on enforced disappearance and arbitrary detention, and five independent rights experts called on the US government to close the site, return detainees home or to safe third countries, and to provide remedy and reparation for their torture and arbitrary detention.

As a newly-appointed member of the UN Human Rights Council, it is particularly important for the United States to “close this ugly chapter of unrelenting human rights violations”, said the experts, who are appointed by the council, but do not speak on behalf of the UN.