The overnight strike caused a fire at the Kaleykino station near the city of Almetyevsk in Russia's Tatarstan region, more than 1200 km from the Russia-Ukraine border, an official from Ukraine's SBU security service said.
The official gave no details of any broader impact on the pipeline.
The Almetyevsk administration said on Telegram that Russian air defences had brought down several drones over the Almetyevsk district, with falling debris igniting a fire in a local industrial zone.
It did not mention the Druzhba pipeline or give any details of possible damage.
The attack, the latest Ukrainian assault on the route, risks exacerbating tensions between Ukraine and its neighbours, Hungary and Slovakia.
Both have accused Kyiv of trying to block oil flows through the pipeline to their refineries.
Shipments of Russian oil to Hungary and Slovakia have been cut off since January 27, when Kyiv says a Russian drone strike hit pipeline equipment in western Ukraine.
Despite Russia's war in Ukraine, Kyiv had continued to transport Russian oil through the pipelines across its territory, although it stopped the transit of Russian gas at the start of last year.
Hungary and Slovakia have threatened to cut off electricity supplies to Ukraine if the oil flow does not resume.
Electricity from Hungary and Slovakia accounts for about 70 per cent of Ukraine's imports.
Half of Ukraine's power generation has been destroyed or seriously damaged by Russian attacks.
Hungary blocked further EU sanctions on Moscow and a big loan for Kyiv on Monday, dealing a blow to Europe's pro-Ukrainian consensus on the eve of the war's fourth anniversary.
In a letter seen by Reuters, Hungarian Prime Minister Viktor Orban told European Council chief Antonio Costa the Druzhba outage was an "unprovoked act of hostility that undermines the energy security of Hungary" and vowed to block the loan until it was solved.
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