Residents run from a fire at a gasoline and oil shop in Aleppo's Bustan Al-Qasr neighbourhood October 20, 2013. Witnesses said the fire was caused by a bullet fired by a sniper loyal to Syrian President Bashar al-Assad at the Karaj al-Hajez crossing, a passageway separating Aleppo's Bustan al-Qasr, which is under the rebels' control and Al-Masharqa neighborhood, an area controlled by the regime. #

A still image taken on August 18, 2016 from a video posted on social media said to be shot in Aleppo on August 17, 2016, shows a boy with bloodied face sitting in an ambulance, after an airstrike, Syria. #

A woman and her baby are seen through the scope of an opposition fighter sniper gun, as she flees the Saif al-Dawla neighborhood of the Syrian northern city of Aleppo, amid heavy street fighting on August 29, 2012. #

Smoke billows following the detonation of explosives placed by Syrian government forces inside a tunnel that was reportedly used by rebels in the northern Syrian city of Aleppo on May 19, 2015. #

Workers document and count dead bodies, which according to the rebel fighters, were members of forces loyal to Syria's President Bashar al-Assad, before burying them in Aleppo on February 23, 2015. The rebel fighters said they killed the men during clashes at Raitan and al-Mallah front lines during an attempt by forces loyal to Syria's President Bashar al-Assad to encircle the northern city and cut off insurgent supply lines. #

Debris cover a street and flames rise from a building following a reported air strike by Syrian government forces on March 7, 2014 during the Friday prayer in the Sukkari neighborhood of the northern city of Aleppo. #

People inspect damage at a site hit by what activists said were barrel bombs dropped by forces loyal to Syria's President Bashar al-Assad in Aleppo's district of al-Sukari on March 7, 2014. #

A child survivor is seen at a hospital in Aleppo's al-Sakhour district, after what activists said was a barrel bomb dropped at Aleppo's Haydariye district by forces loyal to Syria's President Bashar al-Assad, on March 9, 2014. #

Civilians walk near upright buses barricading a street, which serve as protection from snipers loyal to Syria's President Bashar al-Assad, in Aleppo's rebel-controlled Bustan al-Qasr neighborhood on March 21, 2015. #

A fighter with the Free Syria Army (FSA) fires his weapon during heavy clashes with government forces in Izza neighbourhood of the embattled northern city of Aleppo on September 9, 2012. #

Girls who survived what activists said was a ground-to-ground missile attack by forces of Syria's President Bashar al-Assad, hold hands at Aleppo's Bab al-Hadeed district on April 7, 2015. #

Syrians walk past heavily damaged buildings in the neighbourhood of Bani Zeid, on Aleppo's northern outskirts on July 29, 2016, as people come back to the previously rebel-held district, a day after Syrian government forces took control of it. #

A Syrian boy suffering from breathing difficulties is treated at a make-shift hospital in Aleppo after regime helicopters dropped barrel bombs on the rebel-held Sukkari neighborhood of the northern Syrian city on September 6, 2016. The Britain-based Syrian Observatory for Human Rights said the bombs hit the Sukkari neighborhood and that more than 70 people "most of them civilians" were treated for choking symptoms. #