The Kuibyshev oil refinery in Russia's Samara Oblast halted one of two primary refining units, taking half of its capacity offline, after a drone attack overnight on March 23, Reuters reported, citing two unnamed industry sources.
Samara Oblast Governor Dmitry Azarov claimed that a fire had broken out at the Rosneft-owned oil refinery following the reports about explosions. There were no casualties, according to him.
Ukraine's military intelligence agency spokesperson, Andrii Yusov, did not comment on Kyiv's possible involvement in the recent attack, saying an "incident" occurred at the Kuibyshev oil refinery.
The refinery halted operation of the CDU-5, with a production power of 9,500 metric tons per day (70,000 barrels), around half its capacity, according to Reuters.
The news agency calculated that seven refineries have halted refining capacity of 4.6 million tons of oil, or some 7% of the total, due to drone attacks.
In the past weeks, Ukrainian forces have launched a series of drone strikes aimed at damaging Russia's oil industry.
A total of 12 Russian oil refineries were successfully hit in multiple regions deep inside Russian territory as of March 17, Ukrainska Pravda reported, citing an unnamed source in the Security Service of Ukraine (SBU).
Drone attacks on Russia's oil refineries have likely disrupted at least 10% of the country's refinery capacity, according to the U.K. Defense Ministry.
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.
Advisor to Ukraine's Presidential Office head Mykhailo Podolyak denied the reports, saying Kyiv did not receive any such calls from Washington.