KHANKE, Iraq — The 15-year-old girl, crying and terrified, refused to release her grip on her sister’s hand. Days earlier, Islamic State fighters had torn the girls from their family, and now were trying to split them up and distribute them as spoils of war.

The jihadist who had selected the 15-year-old as his prize pressed a pistol to her head, promising to pull the trigger. But it was only when the man put a knife to her 19-year-old sister’s neck that she finally relented, taking her next step in a dark odyssey of abduction and abuse at the hands of the Islamic State.

The sisters were among several thousand girls and young women from the minority Yazidi religion who were seized by the Islamic State in northern Iraq in early August.

The 15-year-old is also among a small number of kidnapping victims who have managed to escape, bringing with them stories of a coldly systemized industry of slavery.

Their accounts tell of girls and young women separated from their families, divvied up or traded among the Islamic State’s men, ordered to convert to Islam, subjected to forced marriages and repeatedly raped.

While many of the victims are still living in areas of northern or western Iraq under the control of the Islamic State, also known as ISIS or ISIL, many others have been sent to Syria or other countries, according to victims and their advocates.

Five girls and women who recently escaped agreed to be interviewed at the end of October. Four of them were in Khanke, a predominantly Yazidi town in the far north of Iraq, and a fifth in the nearby city of Dohuk. Tens of thousands of Yazidi refugees have sought refuge in this region, in vast tent camps and in relatives’ homes, after fleeing their villages around the Sinjar mountains.

The five victims consented to speak publicly only on the condition that their names not be revealed for fear that the Islamic State would punish their relatives.

At first, though, the 15-year-old felt differently. “I want my name used because when the Islamic State reads it, it will be like a revenge for me,” she declared at the outset of her interview, though she soon demurred on the advice of a Yazidi advocate with her, only permitting the use of her initials, D. A. The militants, she said, were still holding most of her immediate family.

The Islamic State itself has openly acknowledged its slavery industry. In an article last month in Dabiq, the group’s online English-language magazine, the Islamic State said it was reviving a custom justified under Shariah.

“One fifth of the slaves were transferred to the Islamic State’s authority to be divided as khums,” a tax on war spoils, and the rest were divided among the fighters who participated in the Sinjar operation, the article said.

Yazidis follow a religion influenced by a medley of faiths, including Zoroastrianism, Judaism and Islam. But the Islamic State regards them as devil-worshiping pagans deserving of enslavement or death. By forcing Yazidi women and girls to marry Islamic State members and become their “concubines,” the article said, the group is helping to protect its fighters against committing adultery.