Firefighters take hours to put out Russian refinery blaze after Ukraine drone strike

MOSCOW (Reuters) -A Ukrainian drone attack caused a fire at a Russian oil refinery that burned for hours on Saturday before it was brought under control in the latest of several damaging strikes this week on Russia's crude oil processing plants.

Ukrainian President Volodymyr Zelenskiy did not address the reported attack but thanked his armed forces, security service and main intelligence directorate "for the new Ukrainian long-range capabilities."

In his nightly video address, he said it had become clear in recent weeks that Ukraine could use its weapons to exploit what he called vulnerabilities in the "Russian war machine," adding, "What our own drones can do is truly a long-range Ukrainian capability."

Interfax news agency quoted the emergencies ministry as saying that "open burning" at the Syzran refinery had been halted, but measures were still under way to extinguish it completely.

It was not clear how the fire would affect production at the plant, which has the capacity to process 8.5 million metric tons of crude oil a year, or 170,000 barrels per day.

An attack on another refinery, Novokuibyshevsky, on Saturday was thwarted, the local governor said. Both plants are owned by Rosneft and located in the Samara region southeast of Moscow, some 800 km (500 miles) from the nearest Ukrainian-controlled territory.

A Ukrainian source told Reuters that Kyiv's SBU intelligence agency had struck three Samara region Rosneft refineries: Syzran, Novokuibyshevsky, and Kuibyshevsky. Russian media have not reported a strike on the Kuibyshevsky refinery, which is located in the city of Samara.

"The SBU continues to implement its strategy to undermine the economic potential of the Russian Federation, which allows it to wage war in Ukraine," the source said.

Ukraine has repeatedly demonstrated its ability to strike deep inside Russia, focusing particularly on energy infrastructure. In the past few days, such attacks have also caused fires at Lukoil's NORSI refinery in Nizhny Novgorod, east of Moscow, and Rosneft's plant in Ryazan, southeast of the capital.

NORSI's main crude distillation unit was damaged, which meant at least half of the refinery's production was stopped, industry sources told Reuters. The Ryazan plant halted units that account for about 70% of its output, sources said.

Disruption to refinery operations has the potential to hit production and force up prices. Even before the latest attacks, Russia had ordered a six-month ban on gasoline exports from March 1 to help keep prices stable, amid rising demand from motorists and farmers, and to allow for maintenance.

In other incidents this week, a drone was destroyed on the outskirts of the Kirishi refinery near St Petersburg on Tuesday while on Wednesday the Novoshakhtinsk refinery in the southern region of Rostov suspended operations briefly after downed drones fell on it.

Russia is voting through Sunday in a three-day presidential election that is virtually certain to give Vladimir Putin six more years in the Kremlin.

(Reporting by Reuters; Writing by Felix Light, Mark Trevelyan and Elaine Monaghan in Washington; editing by Clelia Oziel, Jason Neely, Alexandra Hudson)