Dozens of civilians and fighters in the Sinjar area suffered from nausea and vomiting after self-made missiles were fired at them on February 25, the Kurdistan Region Security Council claimed on its Twitter account.
The shells supposedly contained a chemical substance that caused the symptoms, it added.
The council is working on an investigation in cooperation with the US-led International Coalition for Operation Inherent Resolve, it said.
The substance used in the rockets is suspected to be chlorine, a lethal agent dating back to World War I, secretary general of the Peshmerga, Jabbar Yawar, told Reuters. The use of poison and poisonous weapons in warfare was prohibited by the Chemical Weapons Convention of 1997.
"If confirmed this will be eighth ISIL weaponized chemical attack against Peshmerga. ISIL tactics continue to become more sophisticated, the Kurdish authority said."
This is not the first time Kurdish authorities have blamed ISIS for resorting to the use of chemical weapons, such as chlorine and mustard gas.
This week, lab tests confirmed that sulphur mustard was used on the battlefield in Iraq last August, affecting nearly 35 Peshmerga fighters, a source at the Organization for the Prohibition of Chemical Weapons (OPCW) told Reuters. It was the first known instance of chemical weapons use in Iraq since the fall of Saddam Hussein, the source said.
The news comes as the Iraqi militia discovered two sites with substantial stocks of plastic canisters containing Vinyltrichlorosilane (designated as “Corrosive” UN 1305) in central Iraq, not far from the city of Ramadi – a territory which was controlled by ISIS a short while ago. Some of the canisters were empty, meaning that they had probably already been used by the terrorists.
Earlier in February, Central Intelligence Agency (CIA) Director John Brennan stated ISIS had used chemical weapons on the battlefield, warning that the militant group may have more in its possession, RT reported.
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