A Ukrainian drone attack has damaged a refinery in southern Russia, the governor of the Russian region of Rostov, Vasily Golubiev, said on Thursday.
He said no one was injured, although the attack on the plant in the city of Novoshakhtinsk caused a fire that spread over 50 square metres.
However, the fire looked larger in videos that were shared in social networks during the night.
Russian Telegram channels reported that local residents had noticed the use of air defence and heard explosions.
The Novoshakhtinsk refinery, located close to the Ukrainian border, was previously under aerial attack in April.
Ukraine has been attacking Russian fuel production sites for several months, in an attempt to interrupt Moscow's supplies by using drones capable of travelling longer distances, carrying small explosive charges.
Russia said Ukraine also attacked a fuel depot in the Belgorod region during the night.
Ukraine's military reported Russian attacks during the night using 18 combat drones and two Iskander missiles. Kiev said 17 drones had been shot down.
Russia aimed the two Iskander-M ballistic missiles at the southern Ukrainian region of Dnipropetrovsk, Kiev said, without providing any information about damage caused.
Ukraine has been fending off a full-scale Russian invasion for more than 27 months. Russia occupies almost a fifth of Ukraine's territory, including the Black Sea peninsula of Crimea, which it illegally annexed in 2014.