There is a growing terror threat from women and children returning from Islamic State territory, researchers have claimed, saying their numbers have been significantly underestimated in a new report.

The report highlights a lack of official government data, particularly from Middle Eastern nations, and says females in the terror group are increasingly viewed as potential combatants.

The document, produced by the International Centre for the Study of Radicalisation at King’s College London, says 4,761 of 41,490 – or 13 percent – of the foreigners who affiliated with Islamic State in Iraq and Syria between April 2013 and June 2018 were female.

A further 12 percent, amounting to 4,640 individuals, were minors – however, these numbers are likely to be underestimated, researchers stress.

At least 7,366 – or 20 percent – have now returned to their country of origin or appear to be in repatriation processes to do so, with the figure rising to 55 percent in Western Europe.

“Europol [a European Union police agency] noted that 96 women were arrested for terrorism-related charges in 2014, 171 in 2015, 180 in 2016 (which also highlighted the increasingly operational roles of women), though this fell to 123 in 2017,” the report explains.

“Women and minors are poised to play a significant role in carrying forward the ideology and legacy of [Islamic State] after the physical fall of its ‘caliphate’ in late 2017,” the report warns.

It adds that they have “already demonstrated their prominence as security threats, with numerous foiled and successful attacks plotted and carried out globally.”

Earlier this year, a pair of sisters and their mother went on trial for plotting the UK’s first all-female Islamic State-inspired terror attack on London, spurred on by a fighter in Syria.

Safaa Boular, 18, from the cell became the UK’s youngest convicted female terrorist in June. Researchers also highlight the 2015 San Bernardino attack, in which a woman played a key role.

“We have young children – five to 14 years – these are taken by their parents and guardians… they are likely to have undergone psychological training and physical training,” Dr Joana Cook, a senior fellow at the institute and author of the report, commented.

“These children are featured as executioners, combatants, spies, and in the case of young girls, we are seeing brides down to the age of nine years old.”

ICSR Report Launch – From Daesh to 'Diaspora': Tracing the Women and Minors of Islamic State https://t.co/a1Lvz0Rccu — ICSR (@ICSR_Centre) July 23, 2018

“The British citizens that have now been confirmed as returning to the UK have not been differentiated by gender, or age delineation, though women and minors accounted for 23% of British IS [Islamic State] affiliates in Syria and Iraq,” she added, speaking to The Guardian.

“We believe some women may now pose a particular security threat based on several factors. These include the physical security roles and related training that some women have undertaken in [Islamic State]-held territory, and the potential to transfer or apply these skills in other locations, or to their children.

“The narratives within [Islamic State] itself related to women’s roles in combat have also evolved, broadening the circumstances under which women may be asked to take up arms.

“We have also seen women active in [Islamic State]-linked plots (directed or inspired by the group) in countries such as France, Morocco, Kenya, Indonesia and the US, suggesting that women are indeed important to consider as potential threats.”