Authorities in the city of Novorossiysk said falling drone debris sparked a fire at an oil terminal, injuring two people, without naming the facility.
Russia's Astra news outlet said Ukrainian drones struck the Sheskharis oil terminal and depot, the terminus for Russian state-controlled pipeline company Transneft's main oil pipelines in the region.
Images posted by Astra appeared to show smoke rising above the oil terminal, but they could not be verified.
Ukraine did not immediately comment on the attack.
Ukraine has expanded its mid- and long-range strike capabilities, deploying drone and missile technology that it has developed domestically to battle Russia's four-year-old invasion.
Attacks on Russian oil assets that play a key part in funding the invasion have become almost daily occurrences.
Meanwhile, the death toll from a Ukrainian drone strike overnight into Friday on a college dormitory building in Starobilsk, a city in Ukraine's Russia-occupied Luhansk region, rose to 12, Moscow-installed officials said.
Russian President Vladimir Putin on Friday denounced the attack on the dormitory as a "crime" and ordered the military to submit its proposals for retaliation.
He said there were no military or law enforcement facilities near the college.
At a UN Security Council emergency meeting on the strike, held at the request of Russia, Ukrainian Ambassador Melnyk Andrii denied his Russian counterpart's accusations of war crimes, calling them a "pure propaganda show" and asserting that the May 22 operations "exclusively targeted the Russian war machine".
