The vessels were used to supply fuel to the Russian military, and to transport oil and petroleum products in circumvention of international sanctions, the General Staff said on Telegram.It added that a tugboat and a dry cargo ship were also hit.Earlier, Russia's Rostov region governor said that two tankers had been attacked by Ukrainian drones in the region of Taganrog Bay."The tanker crews have been evacuated. A fire broke out as a result of the drone strike. On one of the vessels, the fire is still burning, on the other, the fire has been completely extinguished," governor Yury Slyusar said on Telegram.Air defence units downed 73 Ukrainian drones overnight, the Russian Defense Ministry said.In Russia's Tver region, an oil depot caught fire as a result of a drone attack, acting governor Vitaly Korolyov said, adding that the fire has been contained and no one was injured.