Ukrainian naval drones hit two oil tankers from Russia's so-called shadow fleet as they travelled through the Black Sea, Ukrainian officials have said. Verified footage shows waterborne drones speeding through the waves into the vessels, before detonating into a ball of flame, sending black smoke into the air. The targeted tankers were named by Turkish authorities as the Kairos and Virat, both flagged to Gambia. Both were hit off the Turkish coast on Friday, with the Virat reportedly struck again on Saturday. No casualties were reported. The attacks appear to be an escalation by Kyiv as it tries to hit Russia's oil revenues, which are critical for funding its war in Ukraine.