The United Nations has published a new report documenting allegations of war crimes, crimes against humanity and genocide committed in Iraq by fighters of the Islamic State of Iraq and the Levant (ISIL).

In a document released on Thursday, the UN Human Rights Office published testimonies from 100 people who survived attacks by the armed group in Iraq between June 2014 and February 2015.

The report documents alleged atrocities and abuses committed by the fighters including killings, torture, rape and sexual slavery, forced religious conversions and the conscription of children.

The UN report also details cases of killings, torture and abductions allegedly carried out by Iraqi security forces and Shia militias battling ISIL.

The UN is calling on the Iraqi government to ensure that all accusations are investigated in line with international human rights standards and to publicise the results of the investigations.

Yazidi 'genocide'

The report highlighted an alleged genocide last year against members of the Yazidi sect, a minority religious group considered to be devil worshippers by ISIL.

ISIL, which controls a swathe of territory in Iraq and neighbouring Syria, allegedly launched a series of systematic and widespread attacks on the Yazidi's heartland in Iraq's northern Nineveh province last August. 

The fighters consistently separated out men and boys over the age of 14 to be executed, while younger boys were forced to become child solders and women and girls were abducted as the "spoils of war," according to UN investigators.

"These attacks were aimed at destroying the Yazidi as a group," said Suki Nagra, head of the investigation.

The report, which was ordered by the UN Human Rights Council last September following a request from the Iraqi government, said that some villages "were entirely emptied of their Yazidi population".

Many Yazidi women and girls were sold into sexual slavery or handed over to ISIL members as "gifts," the report said, adding that witnesses had described hearing girls as young as six screaming for help as they were raped in a house used by fighters.

Boys as young as eight were forced to convert to Islam and given religious and military training, including being forced to watch videos of beheadings, the report said.

"One of the most shocking thing was how organised the attacks have been," Nagra told reporters.

'No community spared'

Other religious and ethnic groups targeted by the fighters include Christians, Turkmen, Kurds, Shias, according to the report.

"No community has been spared," said Nagra, pointing to the thousands of Christians who fled their homes last June after being ordered by ISIL fighters to convert to Islam, pay a tax or leave.

Also in June, ISIL fighters attacked the Badoush prison, dividing the 3,000 inmates into groups, freeing the Sunnis and loading the remaining 600 mainly Shia inmates onto trucks, before driving them to a ravine and shooting them.

The fighters have also targeted anyone perceived to be connected with the Iraqi government, the report said, pointing to the massacre last June of up to 1,700 cadets from the Speicher army base, after they reportedly surrendered.

A separate UN investigation into the situation in neighbouring Syria has also found that ISIL was committing large-scale atrocities in the war-ravaged country, likely amounting to war crimes and crimes against humanity.

Faced with the scope and details of the alleged events, the UN investigators urged the Iraqi government to allow the cases to be tried before the International Criminal Court.

They also called on the UN Security Council to refer the cases to the international court.

"Ensuring that there's no impunity, that there will be accountability" is of the utmost importance, said Hanny Megally, who heads the UN rights office's Middle East branch.

Source: Agencies