When Saliha Ben Ali’s teenage son was killed after leaving Belgium to fight for Islamic State in Syria, she wanted to do what she could to stop other mothers from going through similar heartbreak.

“My message is try to find some help, please speak about this, don’t be alone,” she said at a discussion about the role women can play in fighting the militant group’s violent ideology.

Almost 30,000 foreigners, thousands of them from Western countries, have joined Islamic State and other militant groups to fight in Iraq and Syria, according to a study published by the United States Congress last month.

The organisation Ben Ali founded, Society Against Violent Extremism (SAVE) Belgium, works with families to try to protect young people from extremist recruiters, and helps families whose children have already left for the Middle East.

Social media are a vital tool for extremist recruiters as they enable them to circumvent parents and more moderating religious influences to speak to vulnerable young people directly.

“My son was radicalised in three months only, and when I understood what happened, it was too late,” Ben Ali said at the Women in the World summit in London.

Mothers can help by watching for signs of radicalisation, and getting help when they have concerns, she said.

While all those who fight for Islamic State are men, many women have also left Western countries for Iraq and Syria and are critical to the group’s survival, said Sasha Havlicek, director of the Institute for Strategic Dialogue, a London-based think-tank.

“Islamic State’s plan isn’t just about foreign fighters, it’s about building a state,” she told the Thomson Reuters Foundation in an interview.

Islamic State’s plan isn’t just about foreign fighters, it’s about building a state

The group controls swathes of territory in eastern Syria and northern Iraq, where it has declared an Islamic caliphate.

Though extremist groups have recruited women throughout history, the way in which Islamic State systematically targets them is “unprecedented” according to Havlicek, citing her research on the social media activity of women who have gone to join the militant group.

A picture of Sabri stands on a table next to his mother’s desk.

While there has been a levelling off of new male fighters, there has been an increase in women and families arriving, she said, often marrying other foreign fighters.

“Women are not a sideshow, they (Islamic State) have had a very explicit and concerted strategy to recruit women and they’ve done incredibly well ... they have a marketing department, and it’s very high-tech,” said Havlicek.

Women who join Islamic State “are rejecting the model of Sex and the City empowerment and saying it doesn’t work for them,” she said.

Societies which value girls’ education are less susceptible to jihadist ideology, while Islamist militant groups seek to rein in women’s rights, said Sara Khan, co-director and founder of Inspire, a British anti-extremism charity.

“Whenever we see religious extremists come to power, one of the first things we see, guaranteed, is the curtailing of women’s rights ... Why is it the Taliban tried to assassinate Malala? Why is it that Boko Haram closed down schools?”

It is vital to confront Islamic State’s claim to religious legitimacy by celebrating the history of Muslims who have embraced women’s rights, and highlighting the fact that the vast majority of those actively opposing the group are Muslims, she said.