TOPSHOT - Fighters of the Free Syrian Army fire an anti-aircraft weapon in Aleppo's rebel-held area of Mashhad, 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. / AFP / STRINGER (Photo credit should read STRINGER/AFP/Getty Images)
