The drones, operated by the SBU and the Special Operations Forces, targeted the flare farm, two primary processing units, and two technological units at the Volgograd oil refinery, an SBU source said.

Russian officials said Monday that Ukrainian drone attacks targeted energy facilities in two regions in southwestern Russia. Volgograd Governor Andrei Bocharov said falling debris from drones destroyed by Russian air defenses sparked fires at an oil refinery.

Recent social media videos show Ukrainian forces using drones similar to IEDs. The drones sit next to roads and then strike Russian military vehicles when they pass.