What is known about the attacks in Russia's Dagestan?

Attacks on churches and synagogues in Russia's Dagestan region killed primarily police officers, officials said Monday, announcing a toll of 19 dead after violence that stoked fears over Islamist violence in the historically restive North Caucasus. The assaults launched on Sunday come just three months after Islamic State group fighters killed more than 140 in a Moscow concert hall, the deadliest terror attack on Russia for almost 20 years. FRANCE 24's International Affairs Editor Douglas Herbert tells us more.