An Iraqi airforce helicopter fires missiles at Islamic State fighters in al-Shura, south of Mosul, Iraq October 29, 2016. REUTERS/Goran Tomasevic

A U.S. Air Force B-52 Stratofortress receives fuel from a U.S. Air Force KC-10 Extender at an undisclosed location near Iraq, Oct. 26, 2016. The B-52 approximately carries 70,000 pounds of armament in the support of the liberation of Mosul, Iraq. (U.S. Air Force photo by Senior Airman Tyler Woodward)

A Royal Danish air force F-16 separates from a KC-10 after refueling near Iraq, Oct. 26, 2016. The RDAF F-16s are providing close air support with several other coalition airframes working to liberate the city of Mosul, Iraq. (U.S. Air Force photo by Senior Airman Tyler Woodward)

A French air force Dassault Rafale receives fuel from a KC-10 near Iraq, Oct. 26, 2016. The Dassault Rafale is a twin-engine, multi-role fighter equipped with diverse weapons to ensure its success as a omnirole aircraft. The Rafale has flown in combat missions in several countries including Afghanistan, Libya, Syria and now it's supporting the liberation of Mosul in Iraq. (U.S. Air Force photo by Senior Airman Tyler Woodward)

A U.S. Marine Corps EA-6B Prowler separates from a KC-10 Extender refueling operation near Iraq, Oct. 26, 2016. Prowlers specialize in interrupting enemy electronic activity and obtaining tactical electronic intelligence within the combat area. The Prowler has provided protection for strike aircraft, ground troops and ships by jamming enemy radar and communications in the support of the liberation of Mosul, Iraq. Air Force photo by Senior Airman Tyler Woodward

An Iraqi army helicopter flies over the town of al-Shura, which was recaptured from Islamic State (IS) on Saturday, south of Mosul, Iraq October 30, 2016. REUTERS/Zohra Bensemra

Iraqi security forces launch a rocket towards Islamic State militants during clashes at the frontline in Ali Rash village, southeast of Mosul, Iraq, November 3, 2016. REUTERS/Alaa Al-Marjani

An Iraqi army helicopter flies over the Shahrazad district of eastern Mosul during fighting with Islamic State fighters, Iraq November 4, 2016. REUTERS/Zohra Bensemra

An army helicopter flies over eastern Mosul's districts, Iraq November 5, 2016. REUTERS/Zohra Bensemra

An Iraqi air force helicopter fires missiles at Islamic State militants in Hammam al-Alil, south of Mosul, Iraq November 6, 2016. REUTERS/Thaier Al-Sudani

An Iraqi air force helicopter fires a machine gun at Islamic State militants south of Mosul, Iraq, November 9, 2016. REUTERS/Stringer

An Iraqi air force helicopter fires missiles at Islamic State militants south of Mosul, Iraq, November 9, 2016. Picture taken November 9, 2016. REUTERS/Stringer

An army helicopter flies over al Khazer refugee camp, Iraq November 11, 2016. REUTERS/Zohra Bensemra

An Iraqi military helicopter flies over Shahrezad village east of Mosul, Iraq November 11, 2016. REUTERS/Ari Jalal