 -- Shortly after the Sunni militant group the Islamic State in Iraq and Syria (ISIS) retook control of Raqqa earlier this year, it created the al-Khansaa' Brigade, an all-female unit operating in the city. Its purpose is to apprehend civilian women in Raqqa who do not follow the organization's strict brand of Sharia law, including a mandate that all women be fully covered in public and that they be accompanied by a male chaperone.

"We have established the brigade to raise awareness of our religion among women, and to punish women who do not abide by the law," says Abu Ahmad, an ISIS official in Raqqa. "There are only women in this brigade, and we have given them their own facilities to prevent the mixture of men and women."

He says the organization, which has been pushing further into eastern Syria after taking control of the Iraqi city of Mosul and key points on the Iraq-Syria border last month, needs a female brigade to "raise awareness among women, and arrest and punish women who do not follow the religion correctly. Jihad is not a man-only duty. Women must do their part as well."

The women who join the brigade are either women of Raqqa who wanted to take part in ISIS's activities there, or, often, the wives of mujahedeen who have come to fight from other parts of Syria or the region.

Though women are assuming new, more powerful roles across Syria – the U.N. now estimates that one in four displaced families in Syria has a female head – residents here say that any "girl power" wrought by the brigade is mitigated by the harsher restrictions they have been tasked with imposing on Raqqa's women.

"ISIS created it to terrorize women," says Abu al-Hamza, a local media activist. He says the brigade raided the city's Hamida Taher Girls School and arrested 10 students, two teachers and a secretary on the grounds that some of them were wearing veils that were too thin. Others were accused of wearing hair clips under the veil, pinning them in a way that showed too much of their faces.

Al-Hamza says that the women subsequently spent six hours in an ISIS detention center, where they were whipped. "After arresting those women and girls," continues al-Hamza, "they took them to ISIS prisons and locked them in for six hours and punished some of them with 30 whips each."

Zainab is a local teen who was arrested by female members of ISIS four months ago.

"I was walking down the street when a car suddenly stopped and a group of armed women got out," she says. "They insulted me and yelled at me. They took me to one of their centers and kept me locked in a room. Nobody talked to me or told me the reason for my detention. One of the women in the brigade came over, pointing her firearm at me. She then tested my knowledge of prayer, fasting and hijab."

The fighter told Zainab she had been arrested because she had been walking alone, without an escort, and because her hijab was not worn properly. "You should be punished for taking your religion lightly," she told Zainab, before threatening harsher punishment should she be arrested again.

Two hours later, she was released. But for Zainab – and other women here – the message was clear.

"The brigade has created fear among the women and girls of Raqqa," she says. "We've seen how they move, always watching women on the street, raiding schools, arresting students and locking them in for hours."

This article originally appeared on Syria Deeply.