In a report on IS propaganda focussed on women, Europol said that this could "pave the way" for a change in the role of female jihadists in future terror organisations.

"We are talking about especially millennials," Manuel Navarette, Head of Europol's European Counter Terrorism Centre, told reporters in The Hague as he unveiled the report.

"IS propaganda is focussed on women between 16 to 25, a group more vulnerable to these activities and they have access to social media. IS has adapted to the new target".

IS had in particular assigned new and "more active" roles to female jihadists within the organisation, while keeping its fundamentalist ideas about the position of women in society.

"They kept somehow the traditional role given to women: being supportive, taking care of men," Navarette said.

"But then they start asking women to take a different role, to assist as a doctor, to assist in a different way, not only as the traditional housewife."

The Islamic State's "caliphate" in Iraq and Syria fell in March but the group remains active in several countries in the Middle East, Africa, and Asia, as well as still inspiring jihadists through an online presence.

The international community is also torn over what to do with around 4,000 foreign women and 8,000 children linked to IS who remain stranded in Syria and Iraq.

The fear is that the targeting by IS of women for propaganda could pay dividends for jihadists in years to come.

"The worry is that this increase in the involvement of women could pave the way for potentially major changes in the role of jihadi women in the future," the Europol report said.

Navarette said there had been an increase in arrests of women connected to jihadism in France and Britain in particular.

"There could be a kind of relation between the propaganda machine of IS asking, demanding, for more active of specific groups of women and children to be a part of terrorism," he added.

Europol director Catherine De Bolle said that despite the findings law enforcement agencies needed to take a "gender neutral approach" looking at the reasons for radicalisation.

"It's the way to paradise, for both men and women," she added.