The leader of the Islamic State of Iraq and Sham has asked all families around Iraq's northern city of Mosul to circumcise their daughters or face severe punishment.

Abu Bakr al-Baghdadi, leader of the self-declared Islamic State, has ordered the female genital mutilation of two million Iraqi girls to "distance them from debauchery and immorality".

The "fatwa" issued by the Sunni Muslim fighters would potentially affect four million women and girls, the UN resident and humanitarian coordinator in Iraq Jacqueline Badcock told reporters in Geneva by video from Irbil.

"This is something very new for Iraq, particularly in this area, and is of grave concern and does need to be addressed," she said.

Speaking to BasNews, a spokesman for Mosul police, Ahmed Obaydi, said: "Baghdadi's decision to have all women circumcised is, as he claims, to prevent immorality and promote Islamic attitudes among Muslims. The decision was made by Baghdadi as a 'gift' for people in Mosul."

The decision has, however, sparked outrage by human rights organisations, who said that genital cutting exposes women to an increased risk of disease.

Civil rights activist Asil Jamal said: "When ISIS was first arriving in Mosul, people were warmly welcoming them, but as a result of ISIS' horrendous wishes, especially forced female circumcision, it is becoming clear for people that these ISIS militants don't know anything else except torture.

"Now, people in Mosul believe that their decisions are dangerous, especially female circumcision. They believe that it is a violation against their rights," journalist Saad Qasm commented.

The World Health Organisation state that FGM is recognised internationally as a violation of the human rights of girls and women and reflects a deep-rooted inequality between the sexes.

The practice also violates a person's rights to health, security and physical integrity, the right to be free from torture and cruel, inhuman or degrading treatment, and the right to life when the procedure results in death.

Zanun Majid, a citizen in Mosul, told BasNews: "Due to this decision, many girls fear for their lives, not knowing where to flee, otherwise risking severe punishment by staying."

The news comes just days after the UK held the first Girl Summit, co-hosted by Unicef, aimed at mobilising domestic and international efforts to end FGM and child, early and forced marriage within a generation.

Speaking to IBTimes UK, Dr Babatunde Osotimehin, the executive director of the United Nations Population Fund, said: "What we had yesterday was proof that the global community wants to bring an end to FGM and forced marriage."