Islamic State has said it was responsible for the attack and has released what it says is footage from the massacre. “We know that the crime was carried out by the hand of radical Islamists with an ideology that the Muslim world has fought for centuries,” Mr Putin said. He did not directly mention Islamic State, and repeated his assertion that the assailants had been trying to flee to Ukraine, saying there were “many questions” to be examined. “The question that arises is who benefits from this?” Mr Putin said. “This atrocity may be just a link in a whole...