(VOVworld) - Tests by Organization for the Prohibition of Chemical Weapons (OPCW) have confirmed that Islamic State militants used mustard gas in an attack against a Kurdish militia in Iraq in August, 2015. The organization tested samples taken after 35 Kurdish fighters fell sick fighting with Islamic State militants south-west of Erbil, the capital of the semi-autonomous Kurdish region in northern Iraq. This is the first confirmed use of chemical weapons in Iraq since the fall of Saddam Hussein in 2003. The OPCW found that IS had used chemical weapons in fighting with rebel groups in Syria in 2015.