Previously, female members of ISIS were confined to support roles and kept away from the battlefield but the policy appears to have been reversed as US-led military pressure on its main strongholds in Iraq, Syria and Libya intensified and substantial territory began to be lost, The Guardian reported.
It said researchers have described a "drastic U-turn" on deploying female recruits, a new tactic that poses a challenge for security organisations which already have difficulty penetrating extremist networks and identifying potential attackers.
The cell, organised by a known ISIS militant in France, was the first to be entirely female, the report said.
"If at first it appeared that women were confined to family and domestic chores by the terrorist organisation, it must be noted that this view is now completely outdated," French prosecutor Francois Molins told reporters after the four were arrested.
More From This Section
Officials said all were in their teens, had sworn allegiance to ISIS and were in possession of bomb-making material.
Abdelhak Khiame, who leads Morocco's Central Bureau of Judicial Investigations, said the women, believed to have been planning a series of suicide attacks, "got in touch with (ISIS) elements via the internet and were brainwashed into committing destructive acts targeting... Tourist sites in particular".
"It's a concern... There is constant evolution as the pressures on (ISIS) increase, so we are not complacent," said a western European security official.
"Thus far, ISIS has stifled the role of women in the 'caliphate' by limiting them to the house, ensuring they raise the next generation of jihadi militants and provide for their husbands," said Rachel Bryson of the Centre on Religion and Geopolitics here.