A drone attack that set on fire oil storage sites in Russia's southern Rostov region overnight was conducted by the Security Service of Ukraine (SBU), an intelligence source said on Tuesday.

Russian officials said earlier that several oil storage tanks had caught fire after a drone attack in the town of Azov. The source told Reuters the attack struck the Azovskaya and Azovnefteprodukt depots that have a total of 22 fuel tanks. (Reporting by Tom Balmforth; Editing by Alex Richardson)