A S-300 anti-aicraft missile system of the kind Russia says it will supply to Syria goes off behind a RM-75 Armavir missile in Astrakhan, Russia. EPA
A S-300 anti-aicraft missile system of the kind Russia says it will supply to Syria goes off behind a RM-75 Armavir missile in Astrakhan, Russia. EPA

Russian air defences will complicate Syria's crowded skies