Iraqi Shiite fighters from the Popular Mobilisation units ride on the back of a vehicle in the town of Baiji, north of Tikrit, as they fight alongside Iraqi forces against the Islamic State (IS) jihadist group to try to retake the strategic northern Iraqi town for a second time, on June 10, 2015. Baghdad regained control of Baiji -- located on the road to IS hub Mosul and near the country's largest oil refinery -- last year, but subsequently lost it again. AFP PHOTO / AHMAD AL-RUBAYE (Photo credit should read AHMAD AL-RUBAYE/AFP/Getty Images)
