The Organization for the Prohibition of Chemical Weapons (OPCW) on August 17 voiced "serious concern" about reports that the Islamic State (IS) group has used chemical weapons in Iraq.
The OPCW said it was in contact with the Iraqi government and "will examine any substantive reports it receives."
German officials said last week that Kurdish Peshmerga fighters in northern Iraq appear to have been attacked on August 11 with chemical weapons, possibly chlorine or mustard gas – leaving many suffering from "respiratory irritation.”
The allegations have been deemed "plausible" by a U.S. official.
The Wall Street Journal has quoted U.S. officials who said they think the attack used mustard gas, which may have come from stockpiles of banned poisons that Syrian President Bashar al-Assad was forced to get rid of after joining the OPCW in 2013.