UPDATED 6:59 p.m.: Up to 45 people were killed and 70 injured when a train derailed on the outskirts of the northern Spanish city of Santiago de Compostela on Wednesday in one of the country's worst rail disasters.
Bodies covered in blankets lay next to carriages as smoke billowed from the wreckage a few hundred meters away from the entrance to the city's main station.
The train derailed on the eve of the ancient city's main Christian festival when thousands of pilgrims travel in to pack the streets.
"It was going so quickly ... It seems that on a curve the train started to twist, and the wagons piled up one on top of the other," passenger Ricardo Montesco told Cadena Ser radio station.
"A lot of people were squashed on the bottom. We tried to squeeze out of the bottom of the wagons to get out and we realized the train was burning ... I was in the second wagon and there was fire ... I saw corpses," he added.
Another witness told the radio station she had heard an explosion before seeing the derailed train.
A spokesman for the regional government's office described the derailment as an accident. But the wreckage will stir memories of 2004's Madrid train bombing, carried out by Islamists, that killed 191 people.
"We can confirm there was an accident, but we cannot confirm mortalities as yet," the official told Reuters.
The head of the surrounding Galicia region, Alberto Nunez Feijoo, said at least 35 people had died and it was too early to say what had caused the derailment.
The crash happened a day before the city's main festival paying tribute to the remains of St James, one of Jesus' 12 disciples.
The apostle's shrine in the city is the destination of the famous El Camino de Santiago pilgrimage, followed by Christians since the Middle Ages.
The city is also the birthplace of Spanish Prime Minister Mariano Rajoy.
No one was immediately available to comment from Spanish train operator Renfe whose logo was visible on the wrecked carriages.