Both Islamist fighters and Iraqi government forces have killed civilians and committed atrocities in three months of fighting, senior UN officials said in an emergency debate over the conflict on Monday.
There was "strong evidence" that fighters from Islamic State and linked groups had carried out targeted killings, forced conversions, abductions, sexual abuse and torture, UN Deputy High Commissioner for Human Rights Flavia Pansieri told the session.
Iraqi police have executed detainees while Iraqi soldiers have shelled towns and carried out air strikes killing and injuring many civilians, Pansieri said, opening the meeting of the UN Human Rights Council in Geneva.
"Systematic and intentional attacks on civilians may constitute war crimes and crimes against humanity. Individuals, including commanders, are responsible for these acts," she said, referring to crimes committed by both sides.
Pansieri voiced deep concern at persecution of Christians, Yazidis, Shia, Turkmen and other ethnic groups by Islamic State forces that have swept through western and northern Iraq since June, driving 1.2m Iraqis from their homes.
"The reports we have received reveal acts of inhumanity on an unimaginable scale. I am particularly concerned about the persecution that is taking place," Pansieri said.
The one-day session was called by Iraq with the support of allies including the United States. The 47-member state forum is expected to agree to Baghdad's request to send a team of UN experts to investigate crimes committed by Islamic State and others in the conflict.
