A report says two Americans and a Canadian, all holding dual Libyan citizenship, and two other Libyan nationals have faced grave torture while in custody in the United Arab Emirates (UAE).

The Guardian reported the findings on Friday, citing evidence from sources within the UAE, who have asked the paper not to name them.

The Americans, Kamal and Mohammed Eldarat, and the Canadian, Salim al-Aradi, were detained alongside a Libyan national, Issa al Manna, in August 2014. They were held in secret detention without charge until January 2016, when they were charged with supporting terrorism.

The United Nations experts have noted that the men were being tried on a law enacted after their arrest, that they have had limited access to lawyers and their own case files, and that confessions signed during detention may likely be the result of torture.

During the detention period, the four, alongside another Libyan and other foreign nationals, who were likewise being held without charge, were subjected to an assortment of “brutal techniques,” including electric shocks, beatings, and other types of abuses, the daily wrote.

The victims were beaten, sometimes using rods, sometimes in a “boxing ring,” and in cases while suspended from a chain.

Other instances of inhumane treatment, it said, included “prying off fingernails, pouring insects on to the inmates, dousing prisoners with cold water in front of a fan, sleep deprivation for up to 20 days, threats of rape and sexual harassment, and, in two cases, sexual abuse.”

Canadian consular officials documented “visible bruises about two inches in diameter on his left arm and leg” on 46-year-old businessman al-Aradi when they visited him.

In August last year, a year into his detention, UK-based rights group Amnesty International issued a report for administering the torture, saying al-Aradi was in serious condition and needed quick medical treatment.

Since 2011, when some Arab nations, including Libya, started to see themselves engulfed in anti-government protests, the UAE has been exercising a crackdown on dissent and calls for democratic reform in the country.

Human rights organizations have criticized the country’s rights record, blasting it for not having any democratically-elected institutions, as well as for forced disappearances of foreign nationals and Emirati citizens, numerous instances of torture in incarceration, and denying prisoners their right to a speedy trial, and access to counsel.