Yazidi refugees fleeing ISIS, Aug. 2015. Photo: Reuters

GENEVA — ISIS is committing genocide against the Yazidis in Syria and Iraq to destroy the religious community of 400,000 people through killings, sexual slavery and other crimes, United Nations investigators said on Thursday.

Such a designation, rare under international law, would mark the first recognized genocide carried out by non-state actors, rather than a state or paramilitaries acting on its behalf.

The U.N. report, based on interviews with dozens of survivors, said the terrorist militants had been systematically rounding up Yazidis in Iraq and Syria since August 2014, seeking to “erase their identity” in a campaign that met the definition of the crime as defined under the 1948 Genocide Convention.

“The genocide of the Yazidis is ongoing,” it said.

The 40-page report, entitled “They Came to Destroy: ISIS Crimes against the Yazidis”, sets out a legal analysis of the terrorist group’s intent to wipe out the Kurdish-speaking community.

The Yazidis are a religious sect whose beliefs combine elements of several ancient Middle Eastern religions.

“The finding of genocide must trigger much more assertive action at the political level, including at the (U.N.) Security Council,” Paulo Pinheiro, chairman of the commission of inquiry, told a news briefing.

“Almost two years since the attack on Mount Sinjar, nothing has been done to save those people,” he said, referring to the heart of the Yazidi region in northern Iraq stormed by Islamic State in August 2014.

The independent commissioners urged major powers to rescue at least 3,200 women and children still held by ISIS, mainly in Syria, and to refer the case to the International Criminal Court (ICC) for prosecution.