10."The United States is taking sweeping action against Russia's key source of revenue for funding its brutal and illegal war against Ukraine," Treasury Secretary Janet Yellen said.The sanctions include more than 180 oil-carrying vessels of Russia's so-called shadow fleet, a group of tankers routinely used for sanction evasion. Several of these vessels are also reportedly involved in transporting sanctioned Iranian oil.The measures also target two of Russia's major oil producers, Gazprom Neft and Surgutneftegaz, along with dozens of their subsidiaries.Combined, these companies reportedly produce over 1 million barrels of oil daily, generating an estimated $23 billion of revenue annually, according to the U.S. Treasury.The sanctions also extend to dozens of Russian energy officials and corporate executives, further tightening restrictions on Moscow's oil industry.In addition to sanctions, Ukraine has disrupted Russia's oil production with targeted drone strikes on infrastructure.