Ukrainian security services orchestrated an overnight drone attack on an oil refinery in the southern Russian town of Tuapse, a Ukrainian security source told AFP Thursday.Kyiv has ramped up strikes on Russian oil and gas facilities over the past two months, part of what it has called "fair" retaliation for Russian strikes on its own energy infrastructure.The refinery in Tuapse, some 240 kilometers southeast of the Russian-annexed Crimean peninsula, was an "important facility for the enemy," the source told AFP."After two powerful explosions last night, a large-scale fire broke out there.

The primary oil processing unit, namely the vacuum and atmospheric columns, was damaged," it said.Social media footage posted overnight showed bright flames and columns of smoke tearing through the refinery, owned by Russian oil giant Rosneft."A vacuum unit was on fire.

According to preliminary data, there were no casualties," the head of the Tuapse district Sergei Boiko said on Telegram.Almost 100 people and 31 pieces of equipment were scrambled to tackle the blaze, which was finally put out around 5:00 a.m., he said.Ukraine has claimed responsibility for a string of attacks on Russian energy infrastructure in the past two weeks, including a huge inferno at a depot in western Russia last Friday.