A Ukrainian drone crashed into one of Russia's largest oil refining complexes on Saturday, sparking a fire and causing minor damage, a Russian official said.

The complex, which belongs to Russian oil company Bashneft, lies on the outskirts of the central Russian city of Ufa around 1,400 kilometres from the front line in Ukraine.

Videos posted on social media appeared to show a drone drifting towards the facility before exploding in a ball of flames, sending a cloud of smoke into the sky.

"Today, Bashneft's facility was subjected to a terrorist attack by aircraft-type drones," the head of Russia's Bashkortostan region, Radiy Khabirov, said on Telegram.

One drone crashed into the plant, while another was shot down, he said.

"There were no casualties or injuries. The production site sustained minor damage, and a fire broke out, which is currently being extinguished," he added.

A source in Ukraine's GUR military intelligence agency claimed responsibility for the attack.

Since Moscow launched its full-scale military offensive in Ukraine in February 2022, Kyiv has responded with attacks on Russian refineries in an attempt to curb the Kremlin's ability to fund the conflict.

US President Donald Trump on Saturday urged all NATO countries to stop buying oil from Russia in an effort to increase pressure on Moscow to end the conflict. NATO members Turkey, Hungary and Slovakia all continue to purchase oil from Russia.

A wave of Ukrainian attacks on Russian refineries over the summer hit processing capacity at several key sites and pushed fuel prices up at the pump.

The Kremlin described Bashneft's Ufa refining complex in 2016 as"one of the largest in the country", saying it produced more than 150 types of oil products.