Russia observes a day of national mourning on Sunday after the massacre in a concert hall in Moscow. This is the deadliest attack on European soil claimed by the jihadist group Islamic State (IS) The Kremlin announced on Saturday the arrest of 11 people "including four terrorists involved in the attack" The toll of 133 dead and around a hundred injured is expected to rise further, according to the authorities.
Searches in the rubble of the building ravaged by flames and whose roof partially collapsed are continuing and could take days.