President Vladimir Putin has taken a risk by launching airstrikes against Islamists in Syria because they could incite militants to seek revenge by attacking targets inside Russia.
The Kremlin has largely contained Islamist violence in Russia by cracking down hard but the bombardment of Syria could prompt global jihadis to put Russia on the list of targets they encourage their followers to attack.
Russia has suffered attacks by Islamist militants before, including suicide bombings in Moscow five years ago that killed dozens of people, and more now might turn public opinion against the military intervention in Syria.