On Thursday, independent news agency Arab24 reported that Syrian rebels had uncovered an ISIS prison where female sex slaves were raped and abused with the "worst, most violent torture tools."

The abandoned prison was found by Manbij Military Council fighters, who are a part of the Kurdish-led and United States-supported Syrian Democratic Forces (SDF), in the Syrian city of Manbij, which was recently liberated from the Islamic state.

“We discovered an Islamic State group prison for women, with rooms for groups as well as solitary prisoners,” Ibrahim al-Mohammed told the independent news agency. “We found the worst, most violent torture tools, and may God curse them.”

According to the findings of the Syrian rebels, there are ten small rooms, used as "torture cells," located within the prison. The rooms are filthy; dog bowls filled with dirty water and leftover food are sloppily laid on the stained floor; there are no mattresses; the walls are covered in Arabic writing; and steel, small barred-windows can be found on the large metal doors separating the torture cells from one another.

The Manbij fighters also found narcotics, torture devices and contraception, which is commonly used by ISIS members to "maximize" their sex slaves.

“We found various kinds of pills, including sexual stimulation, contraceptives and narcotic pills which were used by the Islamic State group for torture,” said Omar Mazerli, a militia leader. “They have very strange ways. This place was very hard to find and it is well hidden, but we got here with God’s will and the efforts of the Military Council.”

As The New York Times extensively reported in March, ISIS members have been horrifically "optimizing" their sex slaves, most from the Yazidi religious minority, by force-feeding them birth control and abortion-inducing drugs, as it is customary to only rape their slaves when the woman's womb is "empty."

"To keep the sex trade running, the fighters have aggressively pushed birth control on their victims so they can continue the abuse unabated while the women are passed among them," noted the Times.

“We found the worst, most violent torture tools, and may God curse them.”

Ibrahim al-Mohammed

Women are also beaten in the stomach after being impregnated via rape as a way to kill the unborn child.

“I was telling him: ‘I’m pregnant. In your book it says that you can’t do this.’ He had bloodshot eyes. He acted like he was high,” recalled one former sex slave. After raping her despite her plea, the ISIS member then drove her to the hospital to get an abortion; when she refused, he repeatedly punched her in the stomach to kill the baby.