A freight train derailed on Tuesday in Russia's Bryansk region bordering Ukraine due to an "explosive device" on the tracks, the local governor said.
The announcement of the derailment, which is the second to occur in the region this week, came as Russia was hit by a series of similar attacks while Kyiv says it is preparing for a counteroffensive.
"An unidentified explosive device went off near the Snezhestkaya railway station," Bryansk region governor Alexander Bogomaz said, the day after a similar train derailed in the same area.
"A locomotive and several wagons of the train derailed," he said, adding that there were no casualties.
The station lies about two kilometers outside the regional hub of Bryansk, while the explosion that caused a train to derail and catch fire on Monday occurred near Unecha, closer to the Ukraine border.
Russian Railways put out a statement saying the train had derailed due to "the intervention of unauthorized persons in the work of rail transport".
It did not mention an explosive device.
The state operator said the incident took place at 7:47 pm local time (1647 GMT) between Snezhetskaya and the nearby village of Belye Berega.
It said the train's front locomotive and "around 20 wagons" were derailed and that rail traffic in that section had been suspended.
There have been many reports of sabotage on railways in Russia since Moscow launched its Ukraine offensive, but this week is the first time officials confirmed attacks on this scale.