Ukraine's military has conducted a rare, mass casualty attack deep into central Russia. Long-range drones reached Tatarstan, which lies some 1,200km (or about 750 miles) east of the Ukrainian border.The strikes killed 13 people and wounded at least 75 in what's widely being called one of the most deadly single attacks launched on Russian territory by Ukraine throughout the war.via Reuters"According to the latest information, 13 people have been killed and 75 wounded as a result of the drone attack," on the city of Nizhnekamsk, the Tatarstan region's press service indicated Monday.Nizhnekamsk is an important oil refining hub, and also has a major petrochemical plant, and there have been reports of thick smoke rising above an oil facility near the city. NBC notes that "Ukraine’s General Staff said its forces struck a Taneco oil refinery in Nizhnekamsk, starting a fire."According to more details in regional media:Radmir Belyayev, the mayor of the industrial city of Nizhnekamsk, said drones targeted both civilian and industrial sites during the attack. Besides the more than a dozen fatalities, which included one child, regional authorities said more than 70 people sought medical attention. Unverified reports said the Nizhnekamskneftekhim petrochemical plant, which produces synthetic rubber and plastics, was hit during the overnight attack. Hundreds of drones crossed Russia's skies overnight, with the military saying it shot down 456 Ukrainian drones fired overnight.Ukraine's President Zelensky stated Sunday night, "We do deliver entirely justified responses, and every Russian strike will be met with our response. Russia’s war will be felt more and more at their own home — in Russia."He added: "The only reason this is still continuing is Russia's unwillingness to end this war." Currently there appear to be no negotiations happening, even after the White House signaled it would seek to renew diplomatic efforts toward ending the war."And Ukraine's General Staff has warned, "The Armed Forces of Ukraine will continue systematically implementing measures aimed at bringing the Russian Federation’s armed aggression to an end."At this point, there are hundreds of drones sent on Russia each night, which Ukraine describes as retaliation for heavy Russian ballistic missile attacks on its cities.BREAKING: