U.S. airstrikes and Kurdish Peshmerga fighters helped rescue thousands of Yazidis stranded on a mountaintop in northern Iraq. But hundreds of Yazidi girls and women were captured by ISIS during the prolonged ordeal, and are now being being sold to ISIS fighters in Syria, according the Syrian Observatory for Human Rights, a UK-based monitoring group aligned with the opposition in Syria. In the last several weeks, ISIS has sold about 300 Yazidi women and underage girls it abducted in Iraq, according to the group. Assyrian Christian women have also been sold to ISIS fighters. These young women are considered "slaves of the spoils of war with the infidels," the monitoring group reported. The terrorists sold the women for about $1,000 each, after a forced conversion to Islam so they are "eligible" to marry ISIS fighters. An Iraqi Christian refugee named Rwaa fled the Christian city of Qaraqosh, and reported to the BBC on August 8th that ISIS is raping and selling Christian women. "We fled last night, actually at 3 a.m. in the morning. We were at home when someone came and told us to, 'Leave! Leave!' We left with our clothes only. We didn't even take our passports. And (crying) we have no place to go because no one wants us here. They took everything from us... They took the women. They raped them. They are selling them. For God Sakes, they are selling them! What century are we?" The Syrian monitoring group documented at least 27 cases of women who were sold and married to ISIS militants in the Aleppo suburbs, Raqqa suburbs and Al-Hassakah, according to CNN. Both UN officials and Yazidis fleeing ISIS advances in Iraq have reported that ISIS fighters abducted women to be sold into forced marriages. 'We have reports of women being executed and unverified reports that strongly suggest that hundreds of women and children have been kidnapped - many of the teenagers have been sexually assaulted, and women have been assigned or sold to ISIS fighters," said Heiner Beilefeldt, a UN religious rights monitor. Yazidis are a Kurdish-speaking minority who follow a religion closely linked to Zoroastrianism. They are considered "devil worshippers" by ISIS terrorists because of their unorthodox beliefs. Assyrian Christians have ancient roots in the area surrounding Ninevah in northern Iraq, and trace their beginnings to Jonah's preaching. In August, ISIS captured Yazidi villages near Mount Sinjar, which led to significant world attention amid reports of their mass executions and the abduction of Yazidi women.