The report on detention says Israel’s prison service held more than 9,400 “security detainees” as of the end of June, and some have been held in secret without access to lawyers or respect for their legal rights.

A summary of the report, based on interviews with former detainees and other sources, decries a “staggering” number of detainees — including men, women, children, journalists, and human rights defenders — and said such practices raise concerns about arbitrary detention.

“The testimonies gathered by my office and other entities indicate a range of appalling acts, such as waterboarding and the release of dogs on detainees, amongst other acts, in flagrant violation of international human rights law and international humanitarian law,” said U.N. Human Rights Chief Volker Türk in a statement.

Findings in the report, one of the most extensive of its kind, could be used by International Criminal Court prosecutors who are looking into crimes committed in connection with the Oct. 7 events and its aftermath, including Israel’s blistering military campaign that is ongoing in Gaza.

In May, prosecutor of the International Criminal Court (ICC) Karim Khan filed applications for warrants of arrest against Israeli officials including Prime Minister Benjamin Netanyahu and Israeli Defence Minister Yoav Gallant, who are indicted on seven charges including war crimes and crimes against humanity carried out in Gaza since 7 October 2023.