Several oil storage tanks were on fire after a drone attack early on Tuesday in the town of Azov in Russia's southern region of Rostov, officials said.

"According to preliminary data, there are no casualties," Vasily Golubev, governor of the Rostov region that borders Ukraine, wrote on the Telegram messaging app.

Russia's ministry of emergency situations said on Telegram that the fire had spread across 5,000 cubic meters, and that several dozen firefighters with 21 pieces of equipment were battling the blaze.

Reuters could not independently verify the reports. There was no immediate comment from Ukraine. Kyiv has often said that targeting Russia's energy, military and transport infrastructure undermines Moscow's war effort.

The town of Azov is situated on the Don River and is about 16 kilometers from the Sea of Azov.