Massive Iraq death toll 'staggering' and 'underreported'

At least 19,000 people have been killed in just two years of violence in Iraq, while 3,500 Iraqis are being held in slavery by the Islamic State group, it has emerged.

The United Nations described the death toll as "staggering" and that 36,245 had been injured, but warned that the real figures were likely to be much, much higher.

Conservative estimates from the UN only include casualties from 1 January 2014 to 31 October 2015.

Authors and researchers who compiled the report used "very high standards for verification".

With much of the killing taking place in territories IS controls or in places with fierce fighting, verification is often impossible.

"These are the minimum figures... in terms of the impact of the violence on civilians," said UN Assistance Mission for Iraq (UNAMI) chief Francesco Motta.

UN human rights chief Zeid Raad al-Hussein meanwhile said that the toll only included people directly killed in violence and did include those who perished from the broader impact of conflict.

"Even the obscene casualty figures fail to accurately reflect exactly how terribly civilians are suffering in Iraq," Zeid said in a statement.

"The figures capture those who were killed or maimed by overt violence, but countless others have died from the lack of access to basic food, water or medical care."

Compounding the pain for Iraqis is the mass uprooting of civilians, often children.

This includes 3.2 million people described as "internally displaced" in Iraq since the beginning of 2014, including more than 1 million children.

"Many displaced persons are living in under-resourced locations in poor conditions, and are subject to violence and abuse," the report said.

"The violence suffered by civilians in Iraq remains staggering.

'Crimes against humanity'

Following a decade of violence ignited by the 2003 US-led invasion of Iraq, the security situation seemed to gradually improve - until IS' 2014 lightning offensive in northern Iraq.

The report accused IS of "systematic and widespread violence and abuses of international human rights law and humanitarian law", but saw other parties as culpable in the bloodshed.

The UN documented abuses, killings, and abductions by the Iraqi army and allied - generally Shia - militias who are trying to win back land from IS in Sunni-majority parts of Iraq.

However, the UN said it was the IS crimes that were most shocking.

It detailed "numerous examples of killings... in gruesome public spectacles, including by shooting, beheading, bulldozing, burning alive and throwing people off the top of buildings".

It also condemned reports of IS murdering child soldiers who tried to flee.

One example was the IS murder of 18 children in August for having "run away" from battle.

Child soldiers were also used to murder 15 of its fighters for the same reason.

More shocking was the horrific violence inflicted on the most vulnerable in society.

"[IS] subject women and children to sexual violence, particularly in the form of sexual slavery," the report read.

It estimated 3,500 people being held in IS slavery.

"These acts may, in some instances, amount to war crimes, crimes against humanity, and possibly genocide."

Numerous mass graves have also been discovered, and although many date back to the rule of Saddam Hussein others are more recent and part of the growing evidence of IS war crimes in Iraq.