Ukrainian drones strike major oil refinery deep inside Russia, setting it ablaze

Russia is one of the world's biggest energy producers, with oil providing an economic mainstay as its military tries to push deeper into Ukraine in a slow and costly advance more than four years after Moscow launched its full-scale invasion.

Russia is one of the world's biggest energy producers, with oil providing an economic mainstay as its military tries to push deeper into Ukraine in a slow and costly advance more than four years after Moscow launched its full-scale invasion.