The scale of the attack represents a significant escalation in the conflict, showcasing Ukraine's increasing reliance on drones.

Ukraine said on Friday it had struck a Russian oil refinery and a microchip factory in a huge drone attack that caused fires at the refinery's production facilities and an oil pumping station. Russia said hours earlier that its forces had repelled an overnight drone attack,

The General Staff of Ukraine's Armed Forces confirmed an attack overnight that hit Russia's Ryazan Oil Refinery and the Ryazan Thermal Power Plant, leaving them ablaze Thursday morning.