moscow russian president vladimir putin send telegram syrian president bashar al-assad hail break siege deir al-zor syrian government troop kremlin say tuesday kremlin spokesman dmitry peskov tell conference call reporters putin hail breakthrough strategic victory islamic state militants street-to-street fight underway deir al-zor peskov say russian air strike strike islamic state target city tuesday help syrian government troop area swiftly advance say cite russian defence ministry report putin putin telegram syria 's assad hail 'strategic deir al-zor victory