Ukraine intensified cross-border strikes on Russian infrastructure overnight, launching drones and conducting sabotage operations that hit energy plants, shipping and rail transport far from the front line. In Volgograd, a refinery operated by Lukoil with a design capacity of roughly 300,000 barrels a day erupted in flames, the second reported blaze in as many days following an earlier drone strike. Separately, Ukrainian forces said they struck the Samara oil refinery and sank the cargo vessel "Port Olya-4" in the Caspian Sea port of Olya, claiming the ship was loaded with Iranian-supplied Shahed drone components and ammunition. Rail links were also disrupted. Voronezh region governor Alexander Gusev said a drone damaged a power line at one of the country’s largest south-eastern rail hubs, injuring a track technician and briefly delaying trains. The partisan group ATESH said it disabled a relay cabinet on the Rostov–Luhansk line used to move Russian troops, equipment and fuel. Russia’s defence ministry reported that air-defence units destroyed 46 Ukrainian drones in regions west of Moscow overnight, including nine over Voronezh. Kyiv says attacks on refineries, ports and railways are aimed at curbing the Kremlin’s ability to wage war after months of Russian strikes on Ukrainian cities.