By Issy Ronald and Svitlana Vlasova, CNN(CNN) — A Ukrainian drone strike has killed at least 13 people and injured 75 others in Nizhnekamsk, a city in the Tatarstan region deep inside Russia, local authorities said Monday, marking the deadliest attack to hit the country in more than two years. The strike comes as both Russia and Ukraine intensify their aerial attacks against one another, while the frontlines of the war largely stagnate. As Ukraine’s long-range drone technology has improved in recent months, it has demonstrated a newfound ability to frequently strike infrastructure deep inside Russia, like oil refineries, tankers, power substations and broader energy infrastructure as well as warehouses belonging to Russia’s largest online retailer, Wildberries. Attacks on Wildberries’ warehouses last month killed at least eight people in a single day which, up until Monday’s strike on Nizhnekamsk, was the deadliest Ukrainian attack inside Russia. In just one night earlier this month, Russian missiles killed at least 17 people and injured dozens of others in the Kyiv region.