Amnesty International (AI) [advocacy website] released a report [PDF] on Monday detailing new research that reveals individuals who are detained on politically-motivated charges in Egypt are being held in conditions that amount to torture.

AI’s report, “Crushing humanity: the abuse of solitary confinement in Egypt’s prisons,” details the various abuses carried out in 24 documented cases of prisoners whose duration of confinement lasted between “three weeks to over four years.”

Prolonged solitary confinement is defined by the Nelson Mandela Rules [materials, PDF] as “solitary confinement for a time period in excess of 15 consecutive days.” Under international law, solitary confinement should only be used as a measure of last resort.

Najia Bounaim, North Africa Campaigns Director at AI, said [press release] “Egyptian authorities are using [solitary confinement] as a horrifying ‘extra’ punishment” that is “designed to crush their humanity and eliminate their hope in any a better future.” Those detained have reportedly been subjected to abuses including “beatings by prison guards and having their heads repeatedly dunked into a container by human excrement.” Detainees were also given insufficient food and water. The mental and physical abuse has had long-term negative effects on prisoners including panic attacks, hypersensitivity to stimuli, difficulties with concentration and memory, and paranoia.

AI points to political motivators behind the abusive imprisonments. While in some cases the practice was employed to coerce confessions, in most instances AI found several groups of detainees held solely for their past political affiliations and activism. The report documents dozens of detained human rights activists, journalists, members of opposition parties and participants in public protests. Egyptian authorities have rounded up tens of thousands of individuals on political charges since the replacement of former President Mohamed Morsi on July 3, 2013 by President Abdelfattah al-Sisi.