Kurdish Peshmerga fighter keeps watch at Omar Khaled village near Tal Afar, west of Mosul August 24, 2014. Old hostilities between Arabs and Kurds exacerbate fighting with the Islamic State. (Youssef Boudlal/Reuters) GWER, Iraq — Kurdish fighters are struggling to hold on to recent gains against Islamic State militants in Iraq in the face of constant shelling and sniper fire. But Kurds say the jihadists have another weapon: local Arab sympathizers. The Kurds suspect area Arabs have backed the militants in battles that have raged in Iraq’s north over the past month, including a stunning advance by the jihadists. The fighting has displaced thousands of families in a region long known as a flash point for Arab-Kurdish violence. Now many Sunni Arab residents are barred from coming home. “The Arabs here stabbed us in the back, and now they are threatening us” from the villages nearby, a Kurdish intelligence […]