Ukrainian drones hit a Russian oil refinery in the city of Ryazan overnight, causing a fire and damaging equipment at one of Russia's biggest refineries, four industry sources told Reuters on Friday.

In December, Ukrainian drones targeted oil depots and refineries in Smolensk, Oryol, Bryansk and Rostov — an area that had previously been targeted in July. The General Staff of Ukraine’s Armed Forces claimed that the July attack on the Rostov refinery destroyed 1.5 million tons of oil and oil products worth $540 million (£433m).