Three Russian national guard officers have been killed after two trains were derailed in a Ukrainian sabotage attack.
An explosive device detonated on a section of rail track in Russia's western Oryol region late Saturday, governor Andrei Klychkov said.
Early Sunday two trains in separate parts of Russia's western Leningrad region derailed, leaving a train driver dead and disrupting railway traffic, the region's governor Alexander Drozdenko said on Telegram.
A source in Ukraine's military intelligence agency on Sunday claimed responsibility for two of the attacks, but not for the derailment that killed the driver.
The sabotage incidents were the latest to rock Russia's vast railway system, which Kyiv says Moscow uses to deliver troops and fuel to its army fighting in Ukraine.
