Islamic State (Isis) fighters hoping to escape the Iraqi advance through the city of Fallujah have been disguising themselves as female refugees to make it past government lines.

Reports in the Iranian FARS agency and number of other Arabic language websites have claimed six female refugees – described as "beautiful" – had been revealed to be Daesh fighters when questioned by Iraqi troops.

An unnamed security source was quoted by the agency as saying advancing Iraqi forces had recovered women's dresses in one of ISIL's bases. "They used women's dresses and cosmetic make-ups to flee Fallujah city," the source claimed.

Hundreds of Isis fighters fleeing Fallujah have been captured since the beginning of the Iraqi advance in May. Statements from the Iraqi military had confirmed they were posing as refugees – however this is the first time they have been reported to be posing as women – to get out of the city.

Iraqi forces have been screening men and teenage boys leaving Fallujah and crossing their lines. Interrogations can take up to several hours.

Civilians caught up in the advance by Iraqi Army and Popular Mobilisation Forces risk torture at the hands of pro-government Shia militia. Local officials in Anbar province have claimed , five of those detained have died while in the groups' custody.