 We go to the southern Russian Republic of Dagestan now, situated in the region of North Caucasus, bordering Chechnya. It's one of the poorest regions of Russia, with a predominantly Muslim population. It has, in the past, been the scene of Islamist attacks. And then last Sunday, its security forces spent hours in gun battles as militants, apparently supporters of the Islamic State ISIS, attacked the two largest cities, the capital, Makachkala, and Derbent.