Russian refineries are processing more crude oil in the hope of boosting fuel exports after new U.S. sanctions on Russian tankers and traders made exports of unprocessed crude more difficult, two industry sources said and data showed.

Ukraine has hit one of Russia’s biggest oil refineries in a drone strike overnight, Russian media reports have said. Large flames and plumes of smoke rose from the Ryazan Oil Refinery after locals reported explosions shortly before 1am on Sunday,

Videos showed fireballs over a facility in Ryazan, 110 miles southeast of Moscow. Kyiv is seeking to disrupt Russian military logistics and put pressure on the country’s economy by striking its oil industry.