The United Nations is warning that the alleged use of chemical weapons in Mosul, if confirmed, would be a serious violation of international humanitarian law and a war crime.
"This is horrible," says Lise Grande, the humanitarian coordinator in Iraq in a statement on Saturday. "There is never justification none whatsoever for the use of chemical weapons."
The alleged attack occurred this week in eastern Mosul, an area declared fully liberated by Iraqi forces in January in a neighbourhood along the Tigris River that roughly divides the city in two.
Most of western Mosul is still under Islamic State group control despite a handful of recent gains on the city's southwestern edge by Iraqi forces over the past two weeks.