A fire broke out at the Kiubyshev oil refinery in Russia's Samara Oblast overnight on March 23, Russian media outlets claimed.
The report comes amid a series of Ukrainian drone strikes on oil refineries throughout Russia.
Local residents reported explosions at the refinery and said the facility was on fire, according to Russian Telegram news channels.
The fire at the refinery was likely caused by a drone attack, the outlets claimed. Russian officials have not commented on the report.
Ukrainian forces previously struck the Kiubyshev oil refinery on March 16 in a drone strike that also targeted the region's Syzran refinery. Only the Syzran facility caught fire following the attack, Russian officials claimed.
Both refineries are owned by Rosneft, Russia's largest oil company.
Deputy Prime Minister Olha Stefanishyna said on March 22 that Russia's oil refineries are "absolutely legitimate targets" for the Ukrainian military. Her statement followed media reports that the U.S. had asked Ukraine to stop attacking the Russian oil industry.
Presidential adviser Mykhailo Podolyak denied the reports, saying Kyiv did not receive any such calls from Washington.
"Fuel is a primary tool of waging war. Ukraine will destroy fuel infrastructure," Podolyak said.