Ukraine carried out another drone attack on an oil facility deep inside Russian territory, a military intelligence source in Kyiv told AFP on Wednesday.

Kyiv has ramped up strikes on Russian oil and gas facilities over the past two months, part of what it has called "fair" retaliation for Russian strikes on its own energy infrastructure.

The claim comes after the governor of Saint Petersburg said there had been a loud blast at an industrial site outside the northern city.

Local media meanwhile reported that S-400 missiles systems had shot at a drone that crashed on an oil storage facility in the Nevsky district.

"It was a GUR operation," the source told AFP referring to Ukraine's military intelligence services. The source said the target was used for "military purposes".

Kyiv this month has claimed responsibility for two other drone attacks on energy facilities in the surrounding Leningrad region.

Pulkovo airport in Saint Petersburg announced it had resumed normal operations Wednesday morning local time, following unspecified disruptions overnight.

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Both Russia and Ukraine are using explosive-laden drones to attempt to strike targets deep behind the frontlines, and their armed forces regularly claim to have shot down enemy devices over their territory.

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