A Ukrainian drone attack hit a refinery in Russia's Volgograd region causing a fire at the complex, the regional governor said Sunday.

Russia's defense ministry said eight overnight drone attacks were intercepted, including one in the southern Volgograd region.

"During the night of May 12, the air defense and electronic warfare forces fought off a drone on the territory of the Volgograd region," Governor Andrey Bocharov wrote on Telegram.

"The consequences from the fall of a drone followed by a detonation caused a fire on the site of the Volgograd oil refinery," he added.

Bocharov said the fire had been put out and there were no victims.

Owned by Lukoil, the Volgograd refinery says on its website that it is the biggest producer of oil products in southwest Russia.

It was the target of a Ukrainian attack in February, when authorities also said there were no victims.

Ukraine has intensified its drone attacks this year as it seeks to overcome a shortage of military equipment and manpower more than two years since Russia launched the military offensive against its neighbor. 

As Ukrainian forces up attacks inside Russia and on Russia-held areas of Ukraine, energy facilities have been a key target.

Ukraine says the attacks are in response to Russia's targeting of civilians.