By Isabel Coles
ERBIL, Iraq (Reuters) - Kurdish authorities in Iraq said on Friday they believe their Peshmerga forces have been attacked with chemical weapons, possibly chlorine gas, by Islamic State militants.
The Kurdistan Region's Security Council said it was investigating multiple attacks by Islamic State insurgents against Peshmerga positions, including in Makhmour, southwest of Erbil, the capital of the autonomous Kurdish region, earlier this week.
It was the third report of suspected chemical weapons use on the Iraqi battlefield this year.
"Initial reporting indicates chemical agents were fired in the form of projectiles, possibly mortar rounds," the council said in a statement.
"Several Peshmerga officers were treated for dizziness, vomiting and general weakness, while some are receiving treatment for burns."
Chlorine's use as a weapon is prohibited under the 1997 Chemical Weapons Convention. If inhaled, chlorine gas turns to hydrochloric acid in the lungs and can kill by burning lungs and drowning victims in the resulting bodily fluids.
Chemical weapons stockpiles in Iraq and Syria have been destroyed by the Organization for the Prohibition of Chemical Weapons in The Hague.
(This version of the story fixes dateline)
(Writing by Anthony Deutsch; Editing by Robin Pomeroy)