The United States is investigating whether Islamic State militants used mustard gas in an attack on Kurdish forces in Iraq, in the first indication the militant group may have obtained a banned chemical weapon.
The Wall Street Journal on August 13 quoted senior U.S. officials saying they have "credible information" that the agent used in a recent chemical attack was mustard gas.
IS could have obtained the gas in Syria, whose government admitted to having large quantities of the blistering agent in 2013, when it agreed to give up its chemical weapons arsenal, the newspaper said. IS also might have obtained the mustard agent in Iraq.
Kurdish officials said their peshmerga forces were attacked August 12 near Makhmur, 60 kilometers south of Ibril, and the German Defense Ministry said some 60 Kurdish fighters suffered breathing difficulties from the attack -- a telltale sign of chemical weapons.
Germany said the attack appeared to involve chlorine gas shells, which are toxic but not banned like mustard gas.
The White House National Security Council said it was investigating the reports and could not confirm them.