A panel of UN rights experts said the Biden administration's current review of the Guantanamo Bay prison facility should address "Kafkaesque" human rights violations against the 40 prisoners currently held there, which the experts said includes torture and ill-treatment.
In a statement on Tuesday, the experts noted that many of the remaining detainees are elderly and vulnerable after suffering from "unending deprivation of freedom and related physical and psychological torture" that has compromised their physical and mental integrity.
"Many of the individuals currently and previously held at Guantanamo Bay have spent the bulk of their lives in a Kafkaesque situation where the rule of law was meaningless and the coercive and brutal power of the State ascendant," the UN experts said.
"Democracies can and should do better and the United States must clearly put this dark chapter in its history behind it and demonstrate that it is not only prepared to close the prison facilities but ensure that such practices cannot be used again, and that the crimes committed there will not remain unpunished."
Earlier this month, the Biden administration launched a formal study of the military prison with the intention of closing the facility.
"We welcome the goal of closing the detention facility, consistent with our previous calls to end impunity for the human rights and humanitarian law violations committed during the 'war on terror'," the experts said.
The panel, however, also called for independent investigations into the allegations of extraordinary rendition, torture, and secret detention that surround the legacy of the prison.
The experts, which include UN special rapporteur on extrajudicial executions Agnes Callamard and special rapporteur on torture Nils Melzer, urged for "a transparent, comprehensive, and accountability-focused review of the operation and legacy of the prison and the military commissions".
Closing the prison had been a campaign promise of the Obama administration, where Joe Biden served as vice president.
Currently, 40 detainees remain imprisoned at the camp. Six have been cleared for release and 25 others have not been charged or tried for a crime.
In a video hearing on Tuesday, Yemeni detainee Uthman Abdul Rahim Mohammed Uthman made a case for his release before the Periodic Review Board, which decides which detainees are eligible for transfer out of the prison.
Being approved for transfer by the review board requires an inmate to be cleared by six federal agencies: the departments of State, Defence, Justice and Homeland Security, as well as the Office of the Director of National Intelligence (Odni) and the Joint Chiefs of Staff.
The Odni includes the Central Intelligence Agency (CIA), the agency that oversaw the alleged torture of many of those held at the prison.
Nine detainees have either been charged with a crime or convicted through a military tribunal and, therefore, cannot be processed through the review board. Still, legal scholars have argued that the men can be tried and imprisoned in federal facilities.