Ukraine has launched one of the largest drone attacks in history against Moscow, the capital of the Russian Federation, as the war has eclipsed four and a half years in length.

Reports indicate that Ukrainian forces struck at Russia’s energy sector, severely damaging the Kapotnya oil refinery. Kapotnya serves as the city’s largest oil producer, providing more than a third of the fuel used by the city each month.

Multiple drones are reported to have struck civilian areas around Moscow. One video showed a drone striking a high-rise apartment building, resulting in a massive explosion and fire.

The latest strike comes as a mark of defiance against U.S. leadership from Ukraine’s President Volodymyr Zelensky, who was instructed to refrain from hitting Russian energy assets in hopes of stabilizing global fuel markets just one week ago by President Donald Trump.