Islamic State 'committed war crimes', says UN probe

Islamic State (IS) militants have committed "mass atrocities" in Syria and recruited children as fighters, according to a UN probe, which has also accused the Damascus authorities of using chemical agents in eight separate incidents this year.

In their report, the UN investigators say public executions are a "common spectacle" in areas run by IS, one of the militant groups fighting against the Syrian government.

The findings are the result of six months of interviews and evidence collected between January and July this year as part of an inquiry into human rights violations inside Syria, BBC reported Wednesday .

In their report, the UN investigators said IS was waging a campaign of fear in northern Syria, including amputations, public executions and whippings. "Bodies of those killed are placed on display for several days, terrorising the local population," the document says.

"Women have been lashed for not abiding by IS's dress code. In Raqqa, children as young as 10 are being recruited and trained at IS camps."

The conflict between Syrian government forces and several rebel groups began in 2011 in which some 200,000 people have died.

Stating detail of abuses by both sides in the conflict, the report says the Syrian government used barrel bombs on civilian neighbourhoods. "In some instances, there is clear evidence that civilian gatherings were deliberately targeted" by government forces, the investigators said.

"In government prisons, detainees were subjected to horrific torture and sexual assault," they add.

Among other allegations of war crimes committed by President Bashar al-Assad's government is the use of suspected chlorine gas, a chemical agent, in eight separate incidents in April and May of this year.

On Wednesday, IS supporters tweeted pictures allegedly showing militants executing Syrian army soldiers after capturing the government Tabqa airbase near Raqqa in eastern Syria. The pictures have not been verified.

Paulo Pinheiro, the chairman of the UN panel, said the international community has failed "in its most elemental duties - to protect civilians, halt and prevent atrocities and create a path toward accountability".

One of the investigators, Carla del Ponte - a former chief prosecutor of two UN war crimes tribunals - has urged world powers to refer Syria to the International Criminal Court.