Fierce fighting has been raging around Fallujah since Iraq's military launched an offensive on Monday to reclaim the traditionally Sunni-dominated city from IS. The UN says it fears for the safety of an estimated 10,000 families trapped there, who will pay a heavy toll for the liberation of the city. Iraq's airforce has airdropped thousands of leaflets on Fallujah instructing residents to leave and promising them passage through ‘safe corridors’ established by the military to camps outside the city. The government has set up a hotline for residents to call or text if they require evacuation, while state television has broadcast advice to residents to wave white flags over their homes if they can't flee and to stay away from IS facilities and gatherings. Activists say IS has been preventing residents from leaving and has cut many communication lines, leaving thousands potentially caught in the crossfire between government troops, backed by Shiite militia and tribal fighters, and IS.