Iraqi Shiite fighters from the Popular Mobilisation units, fighting alongside Iraqi government forces, display, upside down, the flag of the Islamic State (IS) group during a military operation aimed at the centre of Baiji, some 200 kilometres north of Baghdad on October 19, 2015. Iraqi forces advanced on three fronts against the Islamic State group, flushing out pockets of resistance in and around Baiji and closing in on Ramadi and Hawijah, officers said. AFP PHOTO / AHMAD AL-RUBAYE        (Photo credit should read AHMAD AL-RUBAYE/AFP/Getty Images)