Ukrainian forces have escalated a campaign against Russian energy infrastructure, with a reported overnight attack targeting the Novokuibyshevsk oil refinery in the Samara region. The strike follows attacks on refineries, oil terminals and distribution facilities that have contributed to unscheduled repairs, reduced refinery throughput, fuel disruptions and long petrol queues in Moscow and other regions. Russia has begun importing petrol and temporarily authorised lower-grade Euro 2 fuel, which contains up to 50 times more sulphur than modern Euro 5 and was banned in Russia in 2013. Kyiv says the attacks aim to reduce fuel available for Russia’s military logistics and weaken oil revenue used to finance procurement, including artillery shells and Iranian drones. The latest incident also highlights Ukraine’s long-range strike capabilities and may affect assessments of Russia’s military position. Prediction-market pricing shows a 5.5% YES probability that Russia will capture Sloviansk by December 31, indicating reduced confidence in such an advance. Russian authorities’ response, possible retaliation, further military developments and Institute for the Study of War assessments will be watched for clues about the conflict’s trajectory.