Recruiters for Islamic extremist groups are increasingly targeting French women and girls, with nearly 100 either in Syria or on their way and 175 being monitored at home, security officials say.

The number of those that security officials believe are preparing their trip has climbed exponentially — from just four being monitored in France at the beginning of 2013, to 74 at the beginning of this year, according to a French official who spoke on condition of anonymity to discuss security matters.

French recruits make up about 900 of the approximately 2,000 Europeans who have fought in Iraq and Syria. Security officials fear the fighters will use new-found battlefield skills — and European Union passports — to carry out attacks back home, and are increasingly alarmed about the rise in girls and women.

Five people, including a sister and brother, were arrested Tuesday and Wednesday suspected of belonging to a ring in central France that Interior Minister Bernard Cazeneuve said specialized in recruiting young French women.

The arrests came weeks after a series of detentions of adolescent girls around France, including a 16-year-old caught at the airport in Nice as she prepared to leave for Turkey and ultimately Syria, and three teens who were planning to travel abroad together and corresponded on social networks.

France's Interior Ministry on Tuesday posted a video showing anguished family members of young people who left to fight alongside extremists, including a young man whose 15-year-old sister set out for what she thought was a humanitarian aid mission. She has not returned.

"They told her she would be valued more in Syria than in France. That she was chosen for this," Fouad El Bathy says in the video.

France has western Europe's largest Muslim population, about 5 million people. France is trying to make it harder both to recruit and to leave to fight alongside jihadis. A measure expected to come to vote Wednesday would let the government seize the passports of suspected would-be jihadi fighters and block Internet sites luring French to the battlefield.