Ukraine's military has struck one of Russia's biggest oil refineries in a long-range drone attack, according to reports. The target was the Slavneft-Yanos facility in Yaroslavl, a city hundreds of miles from the Ukraine border. Ukrainian President Volodymyr Zelensky said the strikes are intended to limit the revenues Russia uses to finance its war. The attack is part of a series of Ukrainian drone operations aimed at disrupting Russian oil production and exports, which are a key source of funding for Moscow's military campaign. There was no immediate comment from Russian officials on the extent of the damage or any casualties.