Beheadings are not the only horrors perpetrated by the Islamic State of Iraq and the Levant, known as ISIL. Over the past two months, there has been a tragic stream of reports about thousands of women and girls abducted from their families and sold in markets. These violent extremists are attacking their own women and girls. While captive, these women and children have been tortured, raped, given to ISIL thugs as "brides," or kept as sex slaves. Some have committed suicide to avoid sexual enslavement. Others have been forced to watch as ISIL beat their children to coerce the women into converting to Islam. Some have simply been executed. Hundreds of women and girls have been taken from Iraq to ISIL camps in Syria and never heard from again. We cannot allow these voices, these lives, to be silenced. All of us must stand up for those who are defenseless. Reports indicate that ISIL has abducted between 1,500 to 4,000 women and girls, mainly from Iraq's religious community of Yezidis and other minority groups. Girls as young as 12 or 13 have been forced to marry extremists or sold to the highest bidder -- like cattle at an auction. These are young girls, mothers, and sisters facing imminent rape, trafficking, and forced marriage. These are women and girls who pleaded to be killed in airstrikes rather than be brutalized by ISIL. The stories are heart breaking, and terrifying. One 17-year-old Yezidi girl told an Italian newspaper that she was being kept as a sex slave by ISIL and wished she would be beaten enough to die. A 14-year-old girl was quoted in the Washington Post describing how her brother was killed and she was given to an ISIL leader as a concubine. Such viciousness against innocents exposes ISIL's blatant rejection of the most basic progress we have made as a community of nations and the universal values that bind civilization. Americans can be proud that the United States helped when tens of thousands from the Yazidi community fled to Sinjar Mountain with nothing but the clothes on their backs to avoid genocidal attacks from ISIL. Now, as we galvanize an international coalition to work with the newly formed Iraqi government to confront the evil represented by these extremists, we need to ensure ISIL's horrendous treatment of women and girls is front and center. That's why, when we engage with the Iraqi government, we will be discussing how best to marshal resources to address ISIL's targeting of women and girls and how to make sure those who have been abducted and trafficked are returned to their families. This is not a task for the Iraqi government alone. The international coalition being formed to combat ISIL must also offer resources and expertise to enable a resolute and inclusive Iraqi government to respond in a comprehensive way to this ISIL threat. The de-humanization of women and girls is central to ISIL's campaign of terror, through which it destroys communities, rewards its fighters and feeds its evil. A coalition that fights ISIL must also fight this particularly egregious form of brutality. This week, new UN human rights chief Zeid Ra'ad al Hussein recognized the urgency in this fight and called for "dedicated efforts... to protect religious and ethnic groups, children -- who are at risk of forcible recruitment and sexual violence -- and women, who have been the targets of severe restrictions." The United States continues to offer humanitarian assistance to help those displaced by ISIL advances in northern Iraq, and we will work with the new Iraqi government and the international community as we respond to the ISIL threat against the women and girls of the region. As Secretary of State John Kerry and others have said, preventing this kind of brutalization of women and girls in conflict zones preserves our common humanity. We must come together to ensure we end it. Catherine Russell is the United States ambassador-at-large for global women's issues.