A bomb planted on the rails derailed a freight train in Russia's North Caucasus republic of Dagestan in the early hours of Sunday, a local police source said.
The incident took place at around 3:40 Moscow time (23:40 GMT Saturday) near the Inchkhe station in Dagestan's Karabudakhkentsky district, he said. Eight cars were reportedly derailed as a result, four of them overturned.
No casualties were reported.
The derailment was caused by a bomb explosion, the spokesman said, adding law enforcement officers were working at the scene.
Twenty-seven people were killed and 90 injured when a bomb equivalent to 7 kg (15 lbs) of TNT derailed a high-speed Moscow-St. Petersburg train, Nevsky Express, on November 27, 2009.