A Ukrainian drone barrage set Moscow’s Kapotnya oil refinery ablaze and killed at least two people elsewhere in the surrounding region on Sunday, the final day of Russia’s parliamentary elections. Moscow Mayor Sergei Sobyanin called it the largest drone assault on the capital to date. Russia said its air defenses shot down more than 1,900 drones during the assault.

The refinery, owned by Gazprom Neft, has processing capacity of about 245,000 barrels a day and is a key fuel supplier for the capital region. Sobyanin confirmed damage to a facility on the refinery grounds and said nobody there was hurt. Ukraine’s General Staff said the strike damaged the AVT-6 primary processing unit, an integrated oil processing unit and the isomerization unit.

Ukrainian President Volodymyr Zelensky confirmed strikes on an oil industry facility and a logistics site in the Moscow region. “These are billions of dollars that sustain the war machine,” he said, listing Flamingo and Pelican among the weapons used. Residential buildings were also hit during the attack, and about 400 people were evacuated from an apartment building in Ramenskoye. Flight restrictions disrupted Moscow airports, with Russian media reporting more than 400 delays.