Ukrainian drones overnight struck one of Russia’s largest oil refineries, sparking a fire, according to Russian officials and Ukraine’s military.

The strike on the Kirishi refinery, in Russia’s northwestern Leningrad region, follows weeks of Ukrainian attacks on Russian oil infrastructure that Kyiv says fuels Moscow’s war effort. The facility, operated by Russian oil major Surgutneftegas, produces close to 17.7 million metric tons per year (355,000 barrels per day) of crude, and is one of Russia’s top three by output.

More than three years since Russia’s full-scale invasion of Ukraine, drones have emerged as a key weapon for both sides. Multiple Russian drones crossed into Poland on Wednesday, prompting NATO to send fighter jets to shoot them down and underlining long-held concerns that the fighting might spill over beyond Ukraine’s borders.

According to Ukraine’s General Staff, explosions and a fire were reported at the Kirishi refinery. It posted a photo appearing to show a blaze and clouds of smoke against a night sky.

Regional Gov. Alexander Drozdenko said three drones were downed overnight in the Kirishi area, with falling debris sparking a fire at the facility. He said no one was injured, and the blaze was put out.

Russian officials did not immediately commented on the consequences of the strike. At least 80 Ukrainian drones were shot down overnight over Russia, occupied Crimea and the adjacent Sea of Azov, according to the Russian Defense Ministry.

Russia remains the world’s second largest oil exporter, but a seasonal rise in demand and sustained Ukrainian drone strikes have caused gasoline shortages in recent weeks.

Gas stations have run dry in some regions of the country, with motorists waiting in long lines and officials resorting to rationing or cutting off sales altogether.

To try to ease the shortage, Russia has paused gasoline exports, with officials Wednesday declaring a full ban until Sept. 30 and a partial ban affecting traders and intermediaries until Oct. 31.

Deadly incidents along Russia’s rails

Also in the Leningrad region, a diesel locomotive was derailed during the night, local Gov. Drozdenko said Sunday. The region surrounds but does not include Russia’s second city of St. Petersburg.

Drozdenko said the locomotive’s driver was trapped in his cabin, and later died of his injuries while being transported to a hospital. He added an official probe would check for signs of sabotage.

Separately, a bomb planted along railway lines in Russia’s Oryol region has killed three people, according to reports by local Gov. Andrey Klychkov. He said victims had been inspecting the track, and identified one as a member of Russia’s National Guard.

According to Klychkov’s posts, published late Saturday and Sunday, the incident happened near the town of Maloarkhangelsk, some 200 kilometers (120 miles) from the Ukrainian border. Russian officials did not immediately comment on what caused it.

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