NATO officials say there has been an uptick in Russian submarine activity in the North Atlantic in recent years. REUTERS/Tatiana Meel NATO has expanded its footprint in the North Atlantic in recent years, two Western officers said. This is partially in response to an increased presence of Russian submarines coming out of Murmansk. NATO allies like to monitor Russian naval activity before reaching the open Atlantic. NATO is expanding its footprint across the Arctic and North Atlantic, increa...