Fighters of the Free Syrian Army fire an anti-aircraft weapon in the rebel-held Mashhad area in southeastern Aleppo, on December 12, 2016, as they battle Syrian government forces during an operation to retake the embattled city. The crucial battle for Aleppo entered its “final phase” after Syrian rebels retreated into a small pocket of their former bastion in the face of new army advances. The retreat leaves opposition fighters confined to just a handful of neighbourhoods in southeast Aleppo, the largest of them Sukkari and Mashhad. (Photo by AFP Photo/Stringer)

Women pose for a picture at the entrance of the Carlton Hotel, in the government controlled area of Aleppo, Syria December 17, 2016. (Photo by Omar Sanadiki/Reuters)

Boys walk near a damaged building in the rebel held besieged city of Douma, in the eastern Damascus suburb of Ghouta, Syria December 30, 2016. (Photo by Bassam Khabieh/Reuters)

A young man with the date 25 painted on his face, gives the victory sign in Tahir Square ahead of the first anniversary of the revolution on January 24, 2012 in Cairo, Egypt. (Photo by Jeff J Mitchell/Getty Images)

A young protester takes part in a protest near Tahrir Square to call for the fall of Islamist President on January 24, 2012 in Cairo. (Photo by Mohammed Abed/AFP Photo via The Atlantic)

A man reacts over dead bodies prior to burial in a graveyard after shelling in the rebel held besieged town of Douma, eastern Ghouta in Damascus, Syria, October 24, 2016. (Photo by Bassam Khabieh/Reuters)

Internally displaced Syrian children who fled Raqqa city stand near their tent in Ras al-Ain province, Syria January 22, 2017. (Photo by Rodi Said/Reuters)

A man covered with dust sits on a street following a reported air strike by Syrian government forces in the rebel-held neighbourhood of Sukkari in the northern city of Aleppo on May 30, 2016. (Photo by Baraa Al-Halabi/AFP Photo)