The UK Defense Ministry's report states this.
Citing reports from Ukrainian intelligence services, reconnaissance indicates that Ukraine has recently launched strikes on 12 Russian oil refineries using drones. Specifically, on March 15-16, three major oil refineries in the Samara region were targeted.
The UK Defense Ministry notes that some of the targeted facilities, located approximately 900 km from Ukraine, are among the most remote, underscoring the range of Ukrainian UAV attacks.
British intelligence emphasizes that such strikes inflict financial losses on Russia, impacting the domestic fuel market. Specifically, recent attacks have disrupted at least 10% of the capacities of Russian oil refineries.
Meanwhile, the comprehensive repair of oil refineries may take some time, and due to sanctions, it could be further prolonged.
“According to a Russian Energy Ministry official, there are plans to deploy Pantsir air defence systems to protect the refineries. However, given the size and scale of Russia’s energy industry, it is unlikely that Russia will be able to protect all the vulnerable facilities,” British intelligence emphasizes.