AMMAN: Syrian authorities closed Aleppo airport and canceled all flights, a military source told Reuters early on Saturday as Syrian rebels opposed to President Bashar Assad said on Friday they had reached the heart of the northern city of Aleppo. Syria was promised extra Russian military aid to help the army thwart a takeover by the rebels opposed to President Bashar al-Assad, of the northwestern Aleppo province, two Syrian military sources told Reuters on Saturday. Damascus expects new Russian military hardware to start arriving at Russia"s Hmeimim airbase near Syria"s coastal city of Latakia in the next 72 hours, the sources added.