Iraq's elite counterterrorism forces fire towards extremist positions during fights between Iraqi security forces and Islamic State group during a military operation to regain control of Hit, 85 miles (140 kilometers) west of Baghdad, Iraq, Wednesday, April 13, 2016. (AP Photo/Khalid Mohammed)

Iraqi soldiers gather to go battle against Islamic State militants south of Mosul , Iraq, June 15, 2016. REUTERS

Iraqi government forces patrol the city of Fallujah on June 18, 2016 as they hunt down holdout jihadists after retaking the Islamic State group's last remaining major hub in Iraq (AFP Photo)

An Iraqi security military vehicle is seen on the outskirts of Falluja, Iraq, June 11, 2016. REUTERS/Alaa Al-Marjani

British Royal Air Force Typhoon and Tornado aircraft refuel from a tanker aircraft during a mission over central Iraq September 21, 2016. REUTERS/Petros Karadjias/Pool

An Iraqi military helicopter flies as Iraq's elite counterterrorism forces advance towards the city of Mosul, Iraq, Thursday, Oct. 20, 2016. (AP Photo/Khalid Mohammed)

An Iraqi military helicopter makes emergency landing after exposure to enemy fire during clashes between Iraqi security forces and members of the Islamic State group as Iraqi army advance towards the city of Mosul, Iraq, Thursday, Oct. 20, 2016. (AP Photo/ Khalid Mohammed)

A helicopter of the U.S.-led coalition flies over the town of Bartella, Iraq, Saturday, Oct. 22, 2016. (AP Photo/Khalid Mohammed)