A drone attack sparked a fire at an oil depot in the western Russian city of Penza early Friday, without causing any casualties, the region's governor said.
Social media videos purported to show a column of flames spewing from the site of an oil depot on Penza's eastern suburbs, about 618 kilometers (384 miles) from the front line.
Officials did not elaborate on the origin of the drones, but the Russian defense ministry said its air defenses had intercepted at least 12 Ukrainian drones overnight, including one over the Penza region.
Ukraine, which has targeted Russian energy infrastructure throughout the nearly four-year war in an attempt to sap the country's war chest, did not immediately comment.
"At around 4:00 am (0100 GMT), a drone attack caused a fire at an oil depot in Penza. According to preliminary data, there are no casualties or injuries," governor Oleg Melnichenko said on Telegram.
Relatively inexpensive Ukrainian drones have caused billions of dollars worth of damage to Russian oil and gas facilities.
Kyiv says the attacks are fair retaliation for Russian strikes on its own energy system.
Russian bombardment of Ukraine's energy grid in recent weeks has left thousands of people without heating and power during sub-zero temperatures.