Up to 100 people are feared injured after a passenger train derailed in Russia's southern Volgograd region, Russian news agencies reported on Monday.
The Interfax news agency said that eight train cars had been derailed.
"Paramedics are on the scene," the emergency ministry said, adding that 324 emergency workers were involved.
Emergency helicopters were being scrambled to the scene near the Kotelnikovo station. The train was travelling from Kazan to Adler on the Black Sea.
Unverified video on Telegram showed at least four carriages derailed, some twisted, with people climbing out of one that was on its side beside the rails.
TASS cited unidentified sources in Russian law enforcement as saying that 20 people had been injured when the train collided with a Kamaz truck.