A masked man speaking in what is believed to be a North American accent in a video that ISIS militants released in September 2014 is pictured in this still frame from video obtained by Reuters, October 7, 2014. The FBI said it was seeking information on the man's identity, and issued an appeal for help in identifying individuals heading overseas to join militants in combat. An ISIS security official revealed that when ISIS seized the Yazidi religious minority region of Sinjar in northern Iraq in early August, ISIS militants separated virgin girls from the rest of the captured women for the sole purpose of designating them to be given away as sex prizes to ISIS fighters, a group of anti-ISIS activists reported. In an interview with the Syrian activist group called "Raqqa is Being Slaughtered Silently" and published to the group's website on Saturday, an unnamed ISIS security official stationed in Raqqa highlighted the militant organization's sex slave practices and revealed that Yazidi virgins were filtered out from Yazidi married women and mothers so that they could be awarded to ISIS fighters who contributed on the front lines for the militant group. The ISIS source told the activist group that after battles in northern Iraq, the militants gathered all the detained religious minority women and "captured the virgins, without others." The source said the virgins were then dispersed "exclusively" among the ISIS militants who participated in that particular battle in the region where the virgins were captured. The source added that the militants preferred virgins and did not concern themselves over married or pregnant women. Once the ISIS militant had picked out his virgin, the girl would be forced to convert so that she could marry the militant, the ISIS official said. "After marrying her [and using her for sex], he might decide to divorce her and pass her onto another fighter," the ISIS official said. The ISIS official also said that many of the girls that weren't claimed by fighters in Iraq were brought to Raqqa to be given as gifts to ISIS leaders there. However, ISIS leaders in Raqqa wanted to prevent the public and media from finding out about the militant group's practices of awarding and selling sex slaves. The leaders were not pleased that the girls were brought to Raqqa and ordered their sex slaves to be kept in remote towns in the Syrian countryside. "The inner circle of leaders and security officials, and were careful that this issue should not be known as much as possible to the civilians," the report stated. Although the ISIS leaders in Raqqa are trying to hide the fact that they are shipping sex slaves in and out of Raqqa, the ISIS' practices of shipping sex slaves to Raqqa has been widely reported. A United Nations report from earlier this month that interviewed multiple witnesses stated that over 150 Christian and Yazidi women were transported to Raqqa on Aug. 5 to be sold as sex slaves. Testimony from a 15-year-old Yazid girl who escaped captivity as an ISIS sex slave published in early October states that she and 200 other Yazidi girls were also transported to Raqqa to be sold as well. Although the Raqqa Being Slaughtered Silently article quotes the ISIS officer as saying that the ISIS fighters separated the virgins and suggested that married women or mothers were not being used as sex slaves, the 15-year-old Yazidi girl said that in her experiences, ISIS militants have used married women and mothers as sex slaves and have sometimes chosen not to believe that a woman is married if she has no way to prove it. The Telegraph was the first to report the English analysis of the interview by the Raqqa is Being Slaughtered Silently group, which was conducted in Arabic. However, neither The Telegraph nor the activist group were able to verify the claims.