The UN says that more than 300 civilians have been killed in the Iraqi city of Mosul since the start of a fresh offensive against Islamic State (IS) militants last month.
UN High Commissioner for Human Rights Zeid Ra'ad al-Hussein said in a statement on March 28 that "it is vital that the Iraqi security forces and their coalition partners" avoid the "trap" of attacking IS forces that are operating in populated areas and using civilians to shield them from attacks.
"This is an enemy that ruthlessly exploits civilians to serve its own ends, and clearly has not even the faintest qualm about deliberately placing them in danger," Zeid said.
Iraqi officials and the U.S. Defense Department are probing reports that air strikes by the coalition targeting IS fighters may have killed dozens or even hundreds of people in recent days.
Zeid called for Iraqi and U.S.-led coalition forces to ensure those investigations are transparent.
Iraqi forces, supported by air strikes from coalition war planes, have been battling IS fighters in Iraq's second-largest city for several months.
More than 200,000 civilians have fled west Mosul in the past month but some 600,000 still remain in IS-held parts of the city, according to the UN.