A Ukrainian drone struck a major oil processing plant in Russia's Bashkiria region on Thursday from some 1,500 km (932 miles) away, a Kyiv intelligence source said, its longest-range such attack since the start of the war.
Ukraine also hit two oil depots in southern Russia, as Kyiv tries to undermine Russian forces pressing along front lines on its territory by attacking energy facilities that are crucial to funding the economy and the war.
Russia's emergency service said a drone attack damaged a pumping station building at Gazprom's Neftekhim Salavat oil processing, petrochemical and fertiliser complex in Bashkiria, Russia's largest such plant, state RIA news agency reported.
The governor of the region said the plant was functioning as usual despite the attack. Reuters could not establish where the drone was launched and what kind of device it was. The nearest government-held part of Ukraine is about 1,400 km away.
The Kyiv source said the drone flew 1,500 km, calling it a record, and hit a catalytic cracking unit in an attack that showed "Russian refineries and oil depots serving the military complex cannot feel safe even in the deep rear".
Moscow says such attacks amount to terrorism and has launched what it says are revenge strikes that have pounded Ukraine's energy infrastructure since mid-March, raising fears about the resilience of the Ukrainian power system.
Kyiv has stepped up its drone attacks on oil processing facilities in Russia since the start of the year, disrupting 15% of Russia's oil refining capacity according to an estimate by a NATO official at the beginning of April.
Reuters calculations on April 15 showed that Russia had been able to repair some key oil refineries hit by drones, reducing capacity idled by the attacks to about 10% from almost 14% at the end of March.
REACHING PARITY
Unable to rapidly match Russia's vast arsenal of cruise and ballistic missiles, Kyiv has focused on developing and producing long-range drones so it can hit back at Russia, which has bombed Ukraine throughout the 26-month-old invasion.
The head of the state arms manufacturer said on Wednesday that Ukraine was producing the same number of deep strike drones as Russia, claiming to have reached parity on a key type of weapon Moscow has used for long-range attacks.
The Ukrainian source said that Kyiv's drones also struck two oil depots near the town of Anapa in Russia's southern Krasnodar region causing large-scale fires overnight. Both attacks were conducted by the Security Service of Ukraine (SBU), the source said.
The depots were used as transshipment points to supply fuel to Russian troops in the nearby occupied peninsula of Crimea, the source said.
Russian authorities said a Ukrainian drone attack caused a fire and damaged several oil tanks at a refinery in Krasnodar region. About six drones were destroyed, but debris fell on a facility near the village of Yurovka, sparking a fire, they wrote on the Telegram messaging app.
"The SBU will continue to reduce Russia's economic and logistics potential for waging war," the source said.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
Track Latest News Live on NDTV.com and get news updates from India and around the world