Iraqi pro-government forces fire an anti-tank cannon near al-Sejar village, north-east of Fallujah, on May 25, 2016, as they take part in a major assault to retake the city from the Islamic State (IS) group. Iraqi forces, consisting of special forces, soldiers, police, paramilitary-fighters and pro-government tribesmen, launched a major assault to retake Fallujah, the scene of deadly battles during the US occupation and one of the toughest targets yet in Baghdad's war on the Islamic State group. (Photo by Ahmad Al-Rubaye/AFP Photo)





A man inspects the damage at his home after a bombing in Fallujah, 40 miles (65 kilometers) west of Baghdad, Iraq, Tuesday, May 24, 2016. Clashes between Iraqi government forces and the Islamic State group outside the city of Fallujah briefly subsided on Tuesday, the second day of a large-scale military operation to drive militants out of their key stronghold west of Baghdad. (Photo by AP Photo)





Smoke rises after bombing targeting Islamic State positions in Fallujah, 40 miles (65 kilometers) west of Baghdad, Iraq, Tuesday, May 24, 2016. (Photo by AP Photo)





Iraqi Federal police arrive to join the forces surrounding Fallujah, 40 miles (65 kilometers) west of Baghdad, Iraq, Tuesday, May 24, 2016. (Photo by Rwa Faisal/AP Photo)





Iraqi Federal police covered in dust arrive to join the forces surrounding Fallujah, 40 miles (65 kilometers) west of Baghdad, Iraq, Tuesday, May 24, 2016. (Photo by Rwa Faisal/AP Photo)





Iraqi security forces, allied Shiite Popular Mobilization Forces and Sunni tribal fighters take combat positions outside Fallujah, 40 miles (65 kilometers) west of Baghdad, Iraq, Tuesday, May 24, 2016. (Photo by Rwa Faisal/AP Photo)





Smoke rises from Islamic State group positions as Iraqi security forces and allied Shiite Popular Mobilization Forces and Sunni tribal fighters take cgather outside Fallujah, 40 miles (65 kilometers) west of Baghdad, Iraq, Tuesday, May 24, 2016. (Photo by Rwa Faisal/AP Photo)





An Iraqi Federal policeman perches on a berm outside Fallujah, 40 miles (65 kilometers) west of Baghdad, Iraq, Tuesday, May 24, 2016. (Photo by Rwa Faisal/AP Photo)





Shi'ite fighters ride on a vehicle near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters with Iraqi security forces gather near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters ride in military vehicles near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters ride on a vehicle near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Iraqi security forces ride in a military vehicle near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters with Iraqi security forces gather near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters with Iraqi security forces gather near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Iraqi security forces gather near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





A Shi'ite fighter stands next to a religious flag near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Iraqi federal police advance towards Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





An Iraqi Shi'ite fighter walks with his weapon near Falluja, Iraq, May 24, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters and Iraqi security forces keep watch near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters and Iraqi security forces advance towards Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters and Iraqi security forces advance towards Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





A member of Iraqi security forces sits in the back of a vehicle near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters gather near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





An Iraqi Shi'ite fighter walks with his weapon near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters and Iraqi security forces advance towards Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters and Iraqi security forces gather near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters with iraqi security forces advance towards Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters and Iraqi security forces advance towards Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Shi'ite fighters and Iraqi security forces gather near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





An Iraqi Shi'ite fighter prays near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





A member of Iraqi security forces walks with his weapon near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Smoke rises from clashes near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Iraqi security forces clash with Islamic State militants near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





A tank is seen near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





A member of Iraqi security forces puts the Iraqi flag over a building near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





Iraqi security forces clash with Islamic State militants near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)





An Iraqi security forces sniper looks through the scope of his rifle near Falluja, Iraq, May 25, 2016. (Photo by Thaier Al-Sudani/Reuters)