Long-range Ukrainian drones launched by the SBU Internal Security Service have hit 12 Russian oil refineries since the start of the war, a Ukrainian intelligence source told Reuters on Sunday.

Officials of the southern Krasnodar region of Russia said that at night Ukrainian drones attacked the Slavyansky Refinery, located 70 km north of the regional capital.

A Ukrainian source said that the refinery, which processes about 4.5 million tons of crude oil a year and produces fuel mainly for export, was attacked during an operation organized by the SBU security service and other Ukrainian forces.

“The agency continues to implement the strategy of undermining Russia’s economic potential and reducing the flow of petrodollars that the enemy is sending to the war,” the source said.

“In general, SBU drones have successfully attacked 12 oil refineries in Russia recently.”

This figure does not include the operations of the Ukrainian military intelligence GUR, which also attacked oil refineries with the help of drones, a second intelligence source said.

Russia accuses Ukraine of “terrorist activity” for trying to disrupt the three-day presidential election.

Russian state media reported that drones had attacked oil refineries in several regions in recent weeks, including refineries owned by Rosneft and Lukoil.

Oil and oil products are an important source of income for Russia, which exports them to dozens of countries around the world.

Ukraine has developed and uses long-range drones to try to counter attacks by Russia, which launched a full-scale invasion of Ukraine in February 2022 and has launched long-range missile and drone strikes throughout the war.