UN Special Rapporteur Fionnuala Ni Aolain made the remarks in a report released on Monday after her visit to the US military prison, which is situated on Cuban soil, at the head of a UN team.
"I observed that after two decades of custody, the suffering of those detained is profound, and it's ongoing," Ni Aolain said, adding that mistreatment of inmates at the Guantanamo prison amounted to violation of detainees' fundamental rights and freedoms.
According to Ni Aolain, the detainees, who have been there for close to two decades after being seized as suspects following September 11, 2001 attacks in the United States, have endured a litany of abuse, including forced cell extractions as well as poor medical and mental health care.
Ni Aolain, who is the UN Special Rapporteur on the Promotion and Protection of Human Rights and Fundamental Freedoms while Countering Terrorism, added that the detainees have also had inadequate access to family either by in-person visits or calls.
"The totality of all of these practices and omissions ... amounts in my assessment to ongoing cruel, inhuman and degrading treatment under international law," she said.
The UN special rapporteur added that Washington has so far done nothing to address the rights violations related to the detainees, including their secret seizure and transfer or rendition to Guantanamo in the early 2000s and the extensive torture methods used by US operatives in the first years following the September 11 attacks.
"The systematic rendition and torture at multiple (including black) sites and thereafter at Guantanamo Bay, Cuba ... comprise the single most significant barrier to fulfilling victims' rights to justice and accountability," the UN special rapporteur said, adding that accountability includes apologies, full remedy and reparations for "all victims."
Stressing that closure of the prison "remains a priority," the UN expert said, "The US government must ensure accountability for all violations of international law, both for victims of its counterterrorism practices, present and former detainees, and victims of terrorism."
The UN expert said, "Every single detainee I met with lives with the unrelenting harms that follow from systematic practices of rendition, torture and arbitrary detention," citing "the undue use of restraints and near constant surveillance as current shortcomings."
The Guantanamo Bay prison was set up in 2002 by then-US President George W. Bush and held about 800 inmates at its peak before the number started to shrink. Some 30 prisoners are still languishing there.
US President Joe Biden had promised to close the facility but has yet to present a plan to do so. Human rights advocates are increasingly frustrated with Biden for failing to deliver on his pledge to close the prison, leaving inmates languishing in the notorious offshore detention center with no end in sight.
MNA/PR