MOSCOW — More than 15 policemen and several civilians, including an Orthodox priest, were killed by armed militants in Russia’s southern republic of Dagestan on Sunday, its governor Sergei Melikov said in a video statement early Monday. [time-brightcove not-tgx=”true”] The gunmen opened fire on two Orthodox churches, a synagogue and a police post in two cities, according to the authorities. Russia’s National Anti-Terrorist Committee described the attacks in the predominantly Muslim region with a history of armed insurgency as terrorist acts. Monday, Tuesday and Wednesday were declared days of mourning in the region. Dagestan’s Interior Ministry said a group of armed men shot at a synagogue and a church in the city of Derbent, located on the Caspian Sea.