A Russian freight train derailed Monday in the western region of Bryansk bordering Ukraine after an "explosive device" detonated on the rail tracks, the local governor said.
The apparent attack came a day after a Ukrainian strike killed four people in a Russian village in the Bryansk region and as Kyiv prepared for a widely expected counter-offensive.
"An unidentified explosive device went off, as a result of which a locomotive of a freight train derailed," Bryansk governor Alexander Bogomaz said on Telegram.
There were no casualties, he added.
Bogomaz said the device went off "on the 136th kilometer" of the railroad between regional hub Bryansk and the town of Unecha, towards the border with Ukraine.
Russian Railways said the incident took place on Monday at 10:17 am local time between the town of Unecha and the village of Rassukha in the southwestern corner of the region — some 100 kilometers from the Ukrainian border.
It said the front locomotive and seven wagons derailed "after the intervention of unauthorized persons."
"As a result of the incident, the locomotive caught fire," it said in a statement.
It later said that the fire had been put out by 12.30 pm local time and that passengers of two Moscow-bound trains in the area would be taken by bus to the regional capital Bryansk.
Footage on social media showed the front of the train and several cargo carriages on fire and lying on the grass next to the tracks.
There have been reports of sabotage acts on railroads in Russia and its ally Belarus throughout Moscow's more than year-long Ukraine offensive.
Also on Monday, the governor of the northern Leningrad region, Alexander Drozdenko, said local power lines had been blown up by an "explosive device."
The official said the lines were damaged near the village of Susanino, 60 kilometers south of Russia's second city St. Petersburg and posted images of the lines lying on the ground in a forest.
Drozdenko later said the FSB security service had opened a criminal case on "sabotage."