Russia's air defense systems destroyed several drones as they approached the Ilsky oil refinery in the Krasnodar region near the Black Sea, local officials said on Sunday.
"Several unmanned aerial vehicles (UAVs) tried to approach the territory of the Ilsky oil refinery in the Krasnodar Krai," the region's emergency officials said on the Telegram messaging channel.
"All of them were neutralized, the infrastructure of the plant was not damaged."
The officials did not say who launched the attack. Reuters was not able to independently verify the report.
On Saturday, Moscow said that Ukraine had struck oil pipeline installations deep inside Russia. Kyiv almost never publicly claims responsibility for attacks inside Russia and on Russian-controlled territory in Ukraine.
The Ilsky refinery, near the Black Sea port of Novorossiisk, has a processing capacity of around 6.6 million tons per year. It has been attacked several times this month.