The UN says it has received reports from Iraq that “reveal acts of inhumanity on an unimaginable scale”.

According to BBC News, Deputy Human Rights Commissioner Flavia Pansieri said Islamic State (IS) was believed to have committed systematic and intentional attacks on civilians.

They include targeted killings, forced conversions, slavery, sexual abuse, and the besieging of entire communities.

Pansieri said evidence suggested that Iraqi government forces had killed detainees and shelled civilian areas.

The unrest in Iraq has escalated dramatically in recent months as Islamic State, formerly known as Isis, and allied Sunni rebels have taken control of large parts of northern and western Iraq.

Thousands of people have been killed, the majority of them civilians, and more than a million others have been forced to flee their homes.

On Monday, Sept 1, the UN Human Rights Council debated demands for an emergency mission to be sent to Iraq to investigate whether war crimes and crimes against humanity were being committed.

Addressing the meeting, Pansieri said UN officials continued to gather “strong evidence” that serious violations of international human rights and humanitarian law had been committed in areas under IS control.

Pansieri said Christian, Yazidi, Turkmen, Shabak, Kaka’i, Sabeans and Shia communities had “all been targeted through particularly brutal persecution” and that IS had “ruthlessly carried out what may amount to ethnic and religious cleansing”.

Yazidis have been targeted for extremely harsh treatment. Many men who refused to convert to Islam were reportedly executed, while women and young girls were allotted as slaves to IS fighters. At least 2,250 Yazidi women and children are being held hostage.

Last week, the UN said it had received reports of at least 650 male inmates of Badouch Prison in Mosul being shot dead by IS militants on July 10. Witnesses and survivors said inmates claiming to be Sunni were taken away, while Shia and members of other religious or ethnic communities were ordered into ditches and killed.

In a separate development on Monday, Iraqi officials told the AFP news agency that Kurdish peshmerga fighters and Shia militiamen had retaken Suleiman Bek, a key stronghold for IS over the past 11 weeks.

The north-eastern town is near Amerli, where thousands of mainly Shia Turkmen were besieged by IS until Iraqi forces broke through on Sunday.