An Iraqi journalist reacts after an Islamic State suicide bomber attacked an Iraqi special forces unit with a car bomb during clashes in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic

Iraqi special forces soldiers run during clashes in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic - RTX2PQI3

Iraqi special forces soldiers look at Christian religious books inside a church damaged by Islamic States fighters in Bartella, east of Mosul, Iraq October 21, 2016. REUTERS/Goran Tomasevic TPX IMAGES OF THE DAY - RTX2PW20

An Iraqi army vehicle is seen during an operation to attack Islamic State militants in Mosul, in Qayyara, Iraq, October 22, 2016. REUTERS/Alaa Al-Marjani - RTX2PZ9M

Peshmerga forces fire a mortar towards Islamic state militants' positions in the town of Naweran near Mosul, October 23, 2016. REUTERS/Azad Lashkari - RTX2Q1RK

Wounded Iraqi special forces soldiers react during clashes with Islamic Sates fighters in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic - RTX2PQEN

An Iraqi special forces soldier fires an RPG during clashes with Islamic States fighters in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic TPX IMAGES OF THE DAY - RTX2PQI0

Iraqi special forces soldiers search a building located inside a church compound in Bartella, east of Mosul, Iraq October 21, 2016. REUTERS/Goran Tomasevic - RTX2PW3K

Iraqi army soldiers keep guard over suspected Islamic State militants at a processing center for displaced people in Qayyara, south of Mosul, Iraq October 21, 2016. REUTERS/Zohra Bensemra - RTX2PW39

Smoke rises at Islamic State militants' positions in the town of Naweran near Mosul, Iraq, October 23, 2016. REUTERS/Azad Lashkari TPX IMAGES OF THE DAY - RTX2Q1MA

A Kurdish peshmerga fighter shoots during an operation to attack Islamic State militants in the town of Naweran, near Mosul, October 23, 2016. REUTERS/Azad Lashkari - RTX2Q237

An Iraqi special forces soldier's shadow is pictured among bullet shells as he fires his rifle at Islamic States fighters in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic - RTX2PQF5

An Iraqi special forces soldier fires a rifle during clashes with Islamic States fighters in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic - RTX2PQI8

Iraqi special forces soldiers walk inside a church damaged by Islamic States fighters in Bartella, east of Mosul, Iraq October 21, 2016. REUTERS/Goran Tomasevic - RTX2PW3F

Iraqi army gather after the liberation a village from Islamic State militants, south of Mosul, during an operation to attack Islamic State militants in Mosul, Iraq, October 21, 2016. REUTERS/Thaier Al-Sudan - RTX2PXCB

REFILE - ADDITIONAL CAPTION INFORMATIONIraqi army gather after the liberation of a village from Islamic State militants, south of Mosul, during an operation to attack Islamic State militants in Mosul, Iraq, October 21, 2016, as toxic smoke is seen over the area after Islamic State militants set fire to a sulphur factory. REUTERS/Thaier Al-Sudan TPX IMAGES OF THE DAY - RTX2PXNT

A man returns to his village after it was liberated from Islamic State militants, south of Mosul in Qayyara, Iraq, October 22, 2016. The fumes in the background are from oil wells that were set ablaze by Islamic State militants. REUTERS/Alaa Al-Marjani TPX IMAGES OF THE DAY - RTX2PZNA

Iraqi army guard a checkpoint in Qayyara, Iraq, October 22, 2016. REUTERS/Alaa Al-Marjani - RTX2PZNP

Members of Iraqi forces walk towards Islamic State positions at the town of Safayah near Mosul, Iraq October 23, 2016. REUTERS/Zohra Bensemra - RTX2Q2XX

A convoy of armoured vehicles belonging to international coalition troops drive during the operation against Islamic State militants outside the town of Naweran near Mosul, Iraq October 23, 2016. REUTERS/Azad Lashkari

An Islamic State suicide bomber attacks an Iraqi special forces unit with a car bomb during clashes in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic TPX IMAGES OF THE DAY - RTX2PQGU

IED planted by Islamic States fighters explodes in front of Iraqi special forces vehicles in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic TPX IMAGES OF THE DAY - RTX2PQHY

An Iraqi special forces soldiers waves an Iraqi flag from top of a church damaged by Islamic States fighters in Bartella, east of Mosul, Iraq, October 21. 2016. REUTERS/Goran Tomasevic - RTX2PW3H

Iraqi special forces soldiers pose for a photograph in front of a Islamic States drawing inside a building located inside a church compound in Bartella, east of Mosul, Iraq October 21, 2016. REUTERS/Goran Tomasevic - RTX2PW24

Iraqi pro-government forces are seen in Qayyara, Iraq, October 22, 2016. REUTERS/Alaa Al-Marjani - RTX2PZTN

Smoke rises at Islamic State militants' positions in the town of Naweran, near Mosul, Iraq, October 23, 2016. REUTERS/Azad Lashkari TPX IMAGES OF THE DAY - RTX2Q26D

An Iraqi special forces soldier fires a cannon at Islamic States fighters in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic TPX IMAGES OF THE DAY - RTX2PQDH

Smoke rises from a bomb attack south of Mosul, during an operation to attack Islamic State militants in Mosul, Iraq, October 20, 2016. REUTERS/Thaier Al-Sudani

An Iraqi special forces soldier stands in a Christian cemetery inside a church compound damaged by Islamic States fighters in Bartella, east of Mosul, Iraq October 21, 2016. REUTERS/Goran Tomasevic - RTX2PW3N

IED planted by Islamic States fighters explodes in front of Iraqi special forces vehicles in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic - RTX2PQHV

An Iraqi special forces soldier fires his rifle during clashes with Islamic States fighters in Bartella, east of Mosul, Iraq October 20, 2016. REUTERS/Goran Tomasevic - RTX2PQHZ

Unexploded mortar round is seen during an operation to attack Islamic State militants in Mosul, Iraq, October 21, 2016. REUTERS/Azad Lashkari - RTX2PV6W

Iraqi special forces soldiers search a building located inside a church compound in Bartella, east of Mosul, Iraq October 21, 2016. REUTERS/Goran Tomasevic - RTX2PW29

A Christian Iraqi special forces soldier walks in a church in Bartella, east of Mosul, Iraq October 22, 2016. REUTERS/Goran Tomasevic TPX IMAGES OF THE DAY - RTX2PZBQ

Members of Iraqi forces eat their lunch in front of Islamic States positions at the town of Safayah near Mosul, Iraq October 23, 2016. REUTERS/Zohra Bensemra - RTX2Q2VL