Ukraine claimed responsibility on Sunday for two sabotage operations against the Russian railway network over the weekend, which left at least three dead, according to a source from the Ukrainian military intelligence service (GUR).

The anonymous GUR source told AFP that the intelligence service, in cooperation with Ukrainian army units, carried out Saturday's attack in Russia's Oryol region, as well as another operation on Sunday in the Leningrad region.

The deadliest incident occurred in the Oryol region, where a bomb planted on railway tracks killed three National Guard members. The victims were inspecting the tracks near the town of Maloarkhangelsk, about 200 kilometers from the Ukrainian border.

In the Leningrad region, two trains derailed on Sunday morning in different parts of the western Russian region. Governor Alexander Drozdenko confirmed that a diesel locomotive derailed near the Semrino station in the Gatchina district, where the driver was trapped in his cab and later died while being transported to the hospital.

A second freight train carrying 15 empty tank cars also derailed further south in the same region, but there were no fatalities. Drozdenko said investigators were investigating the possibility of sabotage in both incidents.

The Ukrainian claim marks an escalation in the war of sabotage against Russian infrastructure. Kyiv traditionally does not claim responsibility for such attacks, but frequently applauds them, arguing that Russia uses its rail network to transport troops and military supplies to its forces fighting in Ukraine. In the past, Ukrainian saboteurs have planted explosives on railway tracks specifically to prevent reinforcements and supplies from reaching Russian troops on the front lines.

Ukrainian forces also attacked one of Russia's most important oil refineries overnight Saturday . The General Staff of the Ukrainian Armed Forces confirmed the attack on the Kirishi refinery in the Leningrad region, carried out by units of the Unmanned Systems Forces and Special Operations Forces.

The Kirishi refinery, operated by Surgutneftegas, is one of Russia's top three refineries by production, with a capacity to process between 17.7 and 20 million metric tons per year. The facility produces nearly 80 types of petroleum products and supplies the needs of the Russian Armed Forces.

Governor Drozdenko reported that three drones were shot down during the nighttime attack, and that the debris caused a fire at the facility that was later extinguished. No injuries were reported in this incident.

The Ukrainian strategy seeks to disrupt Russian supply lines and hit the energy infrastructure that fuels Moscow's war effort, as Russia faces fuel shortages in several regions due to a combination of refinery attacks and increased seasonal demand.

The Russian Defense Ministry reported that it shot down at least 80 Ukrainian drones overnight over Russian territory, occupied Crimea, and the Sea of Azov. Additionally, Russian forces attacked Ukrainian infrastructure with long-range drones and shot down 340 Ukrainian drones in the past 24 hours, according to Russian news agencies.

On the land front, in the Dnipropetrovsk region of Ukraine, in the southeast of the country.