The 'Freedom of Russia' Legion's underground group conducted an operation codenamed 'Barrel' targeting Russian oil and railway logistics, according to Ukraine's Main Intelligence Directorate (GUR). The operation reportedly destroyed over 10,000 tons of oil and caused over $10 million in material damage to Russia, with railway tank cars as the target.

The GUR explained that following a series of strikes by Ukrainian defense forces on Russian refineries and port infrastructure, available tank capacity in Russia decreased. This led to a more active distribution and transportation of oil by rail, a shift that the 'Barrel' operation exploited. The Ukrainian intelligence stated that the operation involved extensive preparation, with underground operatives gathering and analyzing logistics information to identify vulnerable areas. The GUR claims that operatives then infiltrated high-security zones and destroyed dozens of tank cars.