German daily Bild reported today that BND intelligence agents collected blood samples from Kurds who were injured in clashes with IS.
It quoted BND chief Gerhard Schindler as saying that the agency has "information that IS used mustard gas in northern Iraq."
Schindler told the paper that the mustard gas either came from old Iraqi stockpiles produced under Saddam Hussein's rule or was manufactured by IS after it seized the University of Mosul.
A senior German intelligence official, speaking on condition of anonymity because he wasn't authorized to discuss the matter publicly, confirmed the comments attributed to Schindler.