It’s not clear to what extent senior ISIS leadership is driving this strategy, especially since the group does not recognize women as equal participants in war. While ISIS refers to its male jihadi attackers as “soldiers” or “fighters,” so far the group has claimed only one woman as its soldier: Tashfeen Malik, who led an attack in December 2015 in San Bernardino, California; other women who have killed in the group’s name are referred to merely as “supporters.”

Yet radicalized women in France are increasingly willing to give their lives for the cause, says Matthieu Suc, author of Femmes de Djihadistes—or Wives of Jihadis. “In different jihadist records, you can see, you can hear, women—often young—regretting not to be able to commit terrorist attacks,” he says. “Theoretically, women want—just like men—to take part in the jihad. That’s the way it goes. That’s the order of things.”

The threat seems to be growing. Already, 24 women and three girls under the age of 18 are in custody in France for alleged extremism offenses, according to the Paris prosecutor’s office. Some 40 percent of French recruits who have joined ISIS in Syria are female, according to the French Interior Ministry, and French authorities said at least 220 women had made the journey to Iraq and Syria to join ISIS as of December 2015. In early September, Paris prosecutor François Molins estimated that as ISIS continues to lose territory to Kurdish and Iraqi forces, “hundreds” of these radicalized women would return to France in the next few months.