At least 56 people died when a train derailed in Galicia in northwestern Spain on Wednesday, according to the AFP news agency.
Official casualty figures have not been released, but the head of the Galicia region, Alberto Nunez, said the death toll had gone up to 56 after he initially put the figure at 35.
Nunez added that 70 people had been injured, with 20 of them seriously hurt.
The Renfe railway company earlier said there were "several dead and injured" in the accident near the city of Santiago de Compostela, but could not immediately give a precise toll.
The train, carrying 238 passengers, started in Madrid and was bound for the northwestern town of Ferrol as the Galicia region, reported AFP.
"It derailed near the station of Santiago de Compostela but we don't yet know why," Renfe said.
Public television TVE repeated appeals from area hospitals for blood donations to help the injured.
A witness told radio Cadena that carriages overturned several times in a bend and came to a halt piled up on each other.
Television footage showed that four carriages had overturned and were lying on the tracks, at least one of them ripped apart with smoke billowing from the train, reported AFP.
The accident happened around 9:00 p.m. local time "for unknown reasons", said a Renfe spokesman.
First pictures showed parts of the locomotive's roof in flames.
The crash came less than two weeks after a passenger train derailed just south of Paris, killing six people and injuring 30 more.
French rail operator SNCF said that derailment may have been caused by a connecting bar that came loose.