Russian troops took control of a Ukrainian naval base in Feodosia, Crimea, on Monday, according to media reports. The attack was reportedly the third on a Ukrainian base in 48 hours, and leaves Russia with control of most of the country's military bases in Crimea. A Ukrainian army officer told Reuters than his colleagues were unarmed when Russian forces entered firing automatic weapons and using stun grenades. Up to 80 Ukrainian servicemen were affected, according to the Ukrainian defense ministry. The seizure comes as G7 leaders hold a summit and after a top NATO military commander warned of a threat from Russia to the eastern part of Ukraine