ISIS has identified a key demographic from which it can derive strength and power: women. From sexual violence to exploiting Western women as public relations ploys, ISIS knows women are critical actors in their regime.

This was the consensus of witnesses speaking to the House Foreign Affairs Committee earlier this week as they outlined ISIS’ atrocities committed against women.

“Simply put, ISIS needs women—needs to control them—to establish its ‘caliphate’ and give rise to the next generation of ISIS,” Chairman Edward Royce said in his opening remarks. “That is why ISIS is investing heavily in recruiting foreign women to join its ranks. And with each girl who becomes brainwashed, ISIS has a new poster child for its jihadi girl-power propaganda.”

Edward Watts, director and producer of the documentary “Escaping ISIS,” said an estimated 4 million women are currently living under ISIS rule and are the primary victims of ISIS’ actions.

“The treatment of women by ISIS is sometimes overshadowed by the terror group’s more spectacular atrocities,” Watts said. “Yet, I would argue no other section of society suffers more on a day-to-day basis at their hands.”

Watts’ documentary exposes ISIS’ abduction of non-Muslim girls and women and how they become sexually enslaved. Furthermore, it documents the rape of women, including those of 9-year-old girls. According to Watts, ISIS establishes markets where they “trade young women like cattle” or rent them to other ISIS members.

ISIS leaders and publications praise these actions.

Watts said Muslim women also face oppression, through the implementation of Sharia law. If a Muslim woman breaks dress code, she may be subject to severe physical punishment. Many of  these women are also forced into marriages with ISIS fighters.

Additionally, ISIS is targeting children. According to Kathleen Kuehnast, director of gender and peacebuilding at the U.S. Institute of Peace, ISIS has recruited more than 400 children just in 2015. Recent reports have suggested that ISIS is mainly interested in children under the age of 14.

“There is nothing childlike about these brides, and there is nothing bride-like about an enslaved girl,” Kuehnast said.

ISIS engages in sexual enslavement with groups it considers to be “heretical to Islam,” including, but not limited to, Shi’is, Yezidis, and Sunni Muslims, said Ariel Ahram, assistant professor of government and international affairs at Virginia Tech.

“ISIS selectively cites medieval Islamic jurists to justify treating people from these groups as spoils, essentially property. They are raped at will.”

Kuehnast said in order to solve this crisis, it is necessary to acknowledge that ISIS’ violence against women is not just a women’s issue. As a result, educating men and boys about gender equality would facilitate change.

“Sexual violence in conflict is a peace and security issue. It cannot be resolved by women alone,” Kuehnast said.Nor can healing happen in isolation. It must be an inclusive effort of the society in which victims and survivors live.”

But the witnesses said there was hope. In the Middle East, there are advocates looking for support to conquer ISIS’ regime and eliminate the transgressions ISIS has committed against women. The witnesses said the U.S. was a beacon of light and had the capacity to lead a global movement to eradicate the terrorist group.

“Every day that ISIS exists, more women will suffer horrendous violence or sexual assault and more people will be subject to indoctrination in their ideas,” Watts said. “The fight against ISIS is all of our fight. It will require time, effort and sacrifice on our part too. But in ending their regime, we all stand to gain.”