Russia's third biggest refinery struck with Ukrainian drone, endangering a chunk of production

MOSCOW, April 2 (Reuters) - Ukrainian drones attacked Russia's third largest oil refinery on Tuesday about 1,300 km (800 miles) from the front lines, hitting a core unit which processes about 155,000 barrels of crude refining per day.

Russian officials said its jamming devices locked onto a Ukrainian drone near Tatneft's (TATN.MM), opens new tab Taneco refinery, which has an annual production capacity of more than 17 million tons (340,000 barrels per day).

A fire broke out at the refinery that was extinguished within 20 minutes, the state RIA news agency said, adding that production had not been disrupted.

Pictures from the scene indicated the drone hit the primary refining unit, CDU-7, at the Taneco refinery. The unit accounts for around a half of the plant's total annual production capacity.

"A drone attack was carried out on one of the enterprises in Nizhnekamsk," Ramil Mullin, the mayor of Nizhnekamsk, said.

"There are no casualties or serious damage. The technological process of the enterprise has not been disrupted."

The attack was one of several in Tatarstan, a highly industrialised region south-east of Moscow, in the early hours of Tuesday.

A Ukrainian intelligence source told Reuters in Kyiv Ukraine had struck a major Russian oil facility in Tatarstan to reduce Russia's oil revenue.

The source also said Ukrainian-made drones hit a facility producing long-range "Shahed" attack drones, causing "significant damage". There was no immediate comment from Moscow.

Ukraine has in recent months begun attacking the oil refineries of Russia, the world's second largest oil exporter, impacting Moscow's highly lucrative trade in refined products.

According to Reuters calculations, around 14% of Russia's refining capacity has been shut down by drone attacks. There is more demand for refined oil products than for Russian crude.

The attacks on Russian refineries - many deep inside the world's largest country - have raised concerns in Washington about the potential for escalation with Russia, which is the world's largest nuclear power.