Testimonies from 55 ex-detainees revealed "inhuman conditions", according to the report by B'Tselem, which said more than a dozen prison facilities were being used as "de facto torture camps".

"The testimonies clearly indicated a systematic, institutional policy focused on the continual abuse and torture of all Palestinian prisoners held by Israel," the report said.

Ex-inmates described "frequent acts of severe, arbitrary violence; sexual assault; humiliation and degradation, deliberate starvation; forced unhygienic conditions (and) sleep deprivation", it added.

The B'Tselem dossier comes a week after a United Nations report said Palestinian prisoners were subjected to treatment that may amount to torture.

On Monday, a panel of UN experts also warned of the "escalating use of torture" by Israel against Palestinian prisoners since the start of the Israeli war on Gaza.

Last month, Israel's military reported that nine soldiers were being held for the suspected abuse of a Palestinian detainee at a facility holding Palestinians arrested from Gaza.

B'Tselem stated that Israeli authorities declared a "prison state of emergency" on October 18, 11 days after the assault on Palestinian territory began.

The report said "unrelenting physical and psychological violence, denial of medical treatment, starvation, withholding of water, sleep deprivation and confiscation of all personal belongings" are now applied across all prisons.

The number of Palestinians in Israeli prisons and detention facilities has almost doubled since before the war to 9,623 by early July, nearly half of them detained without trial and without being informed of the allegations against them, B'Tselem said.

"More than a dozen Israeli prison facilities, both military and civilian, were converted into a network of camps dedicated to the abuse of inmates," the report added.

"Such spaces, in which every inmate is intentionally condemned to severe, relentless pain and suffering, operate as de facto torture camps."

*This story was edited by Ahram Online.