Ukraine has dramatically increased the number of attacks launched against Russian oil refineries in recent months, sparking fuel shortages and price rises in some parts of the country, BBC Verify and BBC Russian have found.
Drone strikes on refineries - some deep inside Russia - soared in August and remained high in September, an analysis of Russian media reports and verified footage showed.
Some 21 of the country's 38 large refineries - where crude oil is converted into useable fuel like petrol and diesel - have been hit since January, with successful attacks already 48% higher than the whole of 2024.
Ordinary Russians appear to be feeling the impact of the strikes, with verified videos showing long queues at petrol stations. Some garages have suspended operations to 'wait out the crisis' rather than work at a loss, one manager told Russian media.
Ukraine's security service, the SBU, did not respond to a request for comment. But President Volodymyr Zelensky has said damaging Russia's oil industry is a key means of forcing Russia to the negotiating table.
The most effective sanctions – the ones that work the fastest – are the fires at Russia's oil refineries, its terminals, oil depots, the Ukrainian leader said in a September address. We have significantly restricted Russia's oil industry, and this significantly restricts the war.
Reported attacks reached a record level in August, with 14 refineries targeted by Ukrainian drones, and eight in September. The increase came after a brief lull coinciding with a flurry of diplomacy, during which an effort was made to broker a ceasefire deal between Kyiv and Moscow.
Some of the strikes have been launched against facilities deep inside Russia. In late September, the SBU successfully hit the Gazprom Neftekhim Salavat oil refinery in the Bashkortostan region twice.
Satellite images showed smoke billowing from the facility - which is more than 1,100km (683 miles) from the Ukrainian border - after the attack.
Kyiv has also attacked some of Russia's most lucrative facilities. A refinery near Volgograd has been targeted six times this year - with an attack in August forcing it to halt operations for a month. The large Ryazan plant near Moscow - capable of producing 340,000 barrels per day - has been hit five times since January.
Ukrainian strikes appear to be pursuing two targets - large refineries essential to civilian supplies and those closer to the border used to supply troops fighting in Ukraine, according to Vladimir Milov, a former deputy energy minister under Vladimir Putin and now an exiled opposition politician.
Ukraine's general staff has previously claimed that refineries in Samara and Saratov have been used as part of military logistics operations. Both regions have been hit by drone strikes in recent weeks, with two of the three plants in Samara region taken offline.
Justin Crump, an ex-British army officer and CEO of the risk consultancy Sibylline, noted that Ukraine's military and security services have now settled on the tactic as a core campaign against Russia's oil and gas industry.
The impact of strikes on fuel supplies appears evident, with numerous refineries forced to suspend operations since August amid increasing petrol prices and empty fuel stations. The Kremlin has urged the public that the situation remains manageable, despite ongoing fuel shortages in certain regions.
