Ukraine struck oil pipeline installations deep inside Russia on Saturday with a series of drone attacks, including on a station serving the vast Druzhba oil pipeline that sends Western Siberian crude to Europe.
This is according to Russian media.
Ukrainian drone attacks inside Russia have been growing in intensity in recent weeks, and the New York Times reported that US intelligence believes Ukraine was behind a drone attack on the Kremlin earlier this month.
Ukraine has not publicly acknowledged launching attacks against targets inside Russia. The Ukrainian defence ministry did not immediately respond to a request for comment on Saturday.
In the Tver region, which lies just northwest of Moscow, two drones attacked a station that serves the Druzhba (Friendship) pipeline, one of the world's largest oil pipelines, the Kommersant newspaper said.
The Tver local council said that a drone had crashed near the village of Erokhino, around 500 km (310 miles) from the border with Ukraine.
The Telegram channel Baza, which has good sources among Russia's security services, said the drones attacked a station serving the Druzhba pipeline.
Druzhba, built by the Soviet Union, has the capacity to pump more than 2 million barrels per day (bpd) but has been severely under-utilised after Europe sought to reduce its dependency on Russian energy after President Vladimir Putin sent troops into Ukraine last year.
Russia's oil pipeline operator Transneft said earlier this month that a filling point on Druzhba in a Russian region bordering Ukraine had been attacked.
In the Pskov region of Western Russia, two drones caused an explosion that damaged an oil pipeline's administrative building, local Governor Mikhail Vedernikov said. The incident occurred near the village of Litvinovo, less than 10 km (6 miles) from Russia's border with Belarus.
"Provisionally, the building was damaged as a result of an attack by two unmanned aerial vehicles," Vedernikov said.
He said there were no casualties and that an operational group that would deliver final conclusions was working at the scene.
In a separate incident, a construction worker was killed near the border with Ukraine in the Kursk region due to shelling from Ukraine, the local governor said.