Update 12:52 p.m. ET: Some journalists have disputed the reports of a female genital mutilation order.
Islamic State militants have ordered women and girls in the northern Iraqi city of Mosul to undergo female genital mutilation, Reuters reported.
"It is a fatwa [or religious edict] of ISIS, we learnt this this morning," United Nations official Jacqueline Badcock told reporters Thursday.
Militants from the Al Qaeda-inspired Islamic State celebrate the group's declaration of an Islamic state in Fallujah, 40 miles west of Baghdad, Iraq, June 30, 2014. (AP Photo)
The fatwa applies to women and girls ages 11 to 46, according to Al Arabiya News. Four million women and girls could be affected.
The Al Qaeda-inspired Sunni militant group, previously known as the Islamic State of Iraq and Syria, has taken over large swaths of Iraq.
"This is something very new for Iraq, particularly in this area, and is of grave concern and does need to be addressed," Badcock said. "This is not the will of Iraqi people, or the women of Iraq in these vulnerable areas covered by the terrorists."