A damaged room in al-Bayan hospital is pictured in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

People ride a cart pulled by a horse near the damaged al-Hakeem hospital, in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

People fill drinking water into gallon jugs, in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

A damaged Civil Defence ambulance is pictured in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

A damaged room in Omar Bin Abdulaziz hospital is pictured in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

A man walks near rubble of damaged buildings, in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

A damaged Civil Defence ambulance is pictured in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

A damaged swimming pool is pictured in a Civil Defence center in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

A man inspects a damaged Civil Defence vehicle in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

People inspect damage in Omar Bin Abdulaziz hospital, in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

People inspect damage in Omar Bin Abdulaziz hospital, in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail

A man removes broken glass from a damaged Civil Defence vehicle in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail TPX IMAGES OF THE DAY

A medic stands behind sandbags in the damaged al-Hakeem hospital, in the rebel-held besieged area of Aleppo, Syria November 19, 2016. REUTERS/Abdalrhman Ismail TPX IMAGES OF THE DAY 

An injured boy sits near a man as they warm themselves by a fire in a rebel held area of Aleppo, Syria November 18, 2016. REUTERS/Abdalrhman Ismail 

A man assists an injured woman inside a field hospital after airstrikes on the rebel held areas of Aleppo, Syria November 18, 2016. REUTERS/Abdalrhman Ismail 

Injured boys react at a field hospital after airstrikes on the rebel held areas of Aleppo, Syria November 18, 2016. REUTERS/Abdalrhman Ismail TPX IMAGES OF THE DAY ATTENTION EDITORS - VISUAL COVERAGE OF SCENES OF INJURY OR DEATH 

An injured boy reacts inside a field hospital after airstrikes on the rebel held areas of Aleppo, Syria November 18, 2016. REUTERS/Abdalrhman Ismail ATTENTION EDITORS - VISUAL COVERAGE OF SCENES OF INJURY OR DEATH 

Medics treat an injured child inside a field hospital after airstrikes on the rebel held areas of Aleppo, Syria November 18, 2016. REUTERS/Abdalrhman Ismail ATTENTION EDITORS - VISUAL COVERAGE OF SCENES OF INJURY OR DEATH 

Men are pictured next to damaged buildings at a site hit yesterday by airstrikes in the rebel held al-Shaar neighbourhood of Aleppo, Syria November 17, 2016. REUTERS/Abdalrhman Ismail 

Men walk past damaged shops at a site hit yesterday by airstrikes in the rebel held al-Shaar neighbourhood of Aleppo, Syria November 17, 2016. REUTERS/Abdalrhman Ismail 

Smoke rises from a rebel held neighbourhood of Aleppo, Syria November 17, 2016. REUTERS/Abdalrhman Ismail 

People inspect the damage at a site hit yesterday by airstrikes in the rebel held al-Shaar neighbourhood of Aleppo, Syria November 17, 2016. REUTERS/Abdalrhman Ismail 

Men salvage belongings from their damaged shops at a site hit yesterday by airstrikes in the rebel held al-Shaar neighbourhood of Aleppo, Syria November 17, 2016. REUTERS/Abdalrhman Ismail 

A girl makes her way through the debris of a damaged site that was hit yesterday by airstrikes in the rebel held al-Shaar neighbourhood of Aleppo, Syria November 17, 2016. REUTERS/Abdalrhman Ismail 

Children collect firewood amid damage and debris at a site hit yesterday by airstrikes in the rebel held al-Shaar neighbourhood of Aleppo, Syria November 17, 2016. REUTERS/Abdalrhman Ismail 

A man demonstrates how to use a homemade alcohol burner inside a workshop in the rebel-held besieged area of Aleppo, due to lack of cooking gas, Syria November 14, 2016. REUTERS/Abdalrhman Ismail 

A man demonstrates how to use a homemade alcohol burner inside a workshop in the rebel-held besieged area of Aleppo, due to lack of cooking gas, Syria November 14, 2016. REUTERS/Abdalrhman Ismail 

A man demonstrates as he pours alcohol into a homemade burner that is produced inside a workshop in the rebel-held besieged area of Aleppo, due to lack of cooking gas, Syria November 14, 2016. REUTERS/Abdalrhman Ismail 

A man walks past a man riding a bicycle near the rubble of damaged buildings in the rebel held area of Old Aleppo, Syria November 14, 2016. REUTERS/Abdalrhman Ismail 

A woman carries a container of water as she walks past a burnt pick-up truck in the rebel held area of Old Aleppo, Syria November 14, 2016 . REUTERS/Abdalrhman Ismail 

Men walk past a tarpaulin and damaged buses erected as protection from snipers in the rebel held area of Old Aleppo, Syria November 14, 2016. REUTERS/Abdalrhman Ismail 

Civilians walk past debris of damaged buildings in the rebel held area of Old Aleppo, Syria November 14, 2016. REUTERS/Abdalrhman Ismail 

A boy inspects boxes inside a grocery shop with low supplies in the rebel-held besieged area of Aleppo, Syria November 12, 2016. REUTERS/Abdalrhman Ismail 

A family's fridge is pictured in the rebel-held besieged area of Aleppo, Syria November 12, 2016. REUTERS/Abdalrhman Ismail 

A family's fridge is pictured in the rebel-held besieged area of Aleppo, Syria November 12, 2016. REUTERS/Abdalrhman Ismail

People stand inside a grocery shop with low supplies in the rebel-held besieged area of Aleppo, Syria November 12, 2016. REUTERS/Abdalrhman Ismail

A girl uses her mobile phone inside a grocery shop with low supplies in the rebel-held besieged area of Aleppo, Syria November 12, 2016. REUTERS/Abdalrhman Ismail

A family's fridge is pictured in the rebel-held besieged area of Aleppo, Syria November 12, 2016. REUTERS/Abdalrhman Ismail

A family's meal is laid on a stove in the rebel-held besieged area of Aleppo, Syria November 12, 2016. REUTERS/Abdalrhman Ismail

A Harakat Nour al-Din al-Zenki fighter watches news about Donald Trump's election as president on his smart phone in the rebel held beseiged area in Aleppo, Syria November 9, 2016. REUTERS/Abdalrhman Ismail TPX IMAGES OF THE DAY

A Harakat Nour al-Din al-Zenki fighter watches news about Donald Trump's election as president on his smart phone in the rebel held beseiged area in Aleppo, Syria November 9, 2016. REUTERS/Abdalrhman Ismail

Men walk in a public park in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

A man eats food that was distributed as aid in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

People walk past rubble of damaged buildings in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

A girl sits in a van driving past damaged buildings in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

People walk past rubble of damaged buildings in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

Children inspect rubble of damaged buildings in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

Men ride bicycles near rubble of damaged buildings in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

A boy breaks a branch to be used as firewood in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

People repair a bicycle near rubble of damaged buildings in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

A man pours fuel into a bottle in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

People walk near rubble of damaged buildings in a rebel-held besieged area in Aleppo, Syria November 6, 2016. REUTERS/Abdalrhman Ismail

A man gives a Koran class inside a damaged house in Tariq al-Bab neighbourhood of Aleppo, Syria November 2, 2016. REUTERS/Abdalrhman Ismail TPX IMAGES OF THE DAY

People walk along a street near damaged buildings in Tariq al-Bab neighbourhood of Aleppo, Syria November 2, 2016. REUTERS/Abdalrhman Ismail

A man gives a Koran class inside a damaged house in Tariq al-Bab neighbourhood of Aleppo, Syria November 2, 2016. REUTERS/Abdalrhman Ismail

People ride a cart pulled by a horse in Tariq al-Bab neighbourhood of Aleppo, Syria November 2, 2016. REUTERS/Abdalrhman Ismail

Graffiti is seen on a damaged building in Tariq al-Bab neighbourhood of Aleppo, Syria November 2, 2016. REUTERS/Abdalrhman Ismail

A mechanic works on a vehicle in Tariq al-Bab neighbourhood of Aleppo, Syria November 2, 2016. REUTERS/Abdalrhman Ismail

Rebel fighters part of the Jabhat Fatah al Sham, attend military training in the besieged rebel held Aleppo, Syria October 26, 2016. Picture taken October 26, 2016. REUTERS/Abdalrhman Ismail

Rebel fighters part of the Jabhat Fatah al Sham, attend military training in the besieged rebel held Aleppo, Syria October 26, 2016. Picture taken October 26, 2016. REUTERS/Abdalrhman Ismail