French President Francois Hollande said on Tuesday two hostage takers who killed a priest in a church in Normandy, northern France, were terrorists who had pledged allegiance to Islamic State, Reuters reported. "Daesh has declared war on us, we must fight this war by all means, while respecting the rule of law, what makes us a democracy," he told reporters at the scene in Saint-Etienne-du-Rouvray, south of Rouen, using an Arab acronym for the Islamist extremist group.