SANTIAGO DE COMPOSTELA, Spain (AP) — Spanish investigators tried to determine today why a passenger train jumped the tracks and sent eight cars crashing into each other just before arriving in this northwestern shrine city on the eve of a major Christian religious festival, killing at least 78 people and injuring more than 140.

Seventy-three people were found dead at the scene of the accident and four died in hospitals, said Maria Pardo Rios, spokeswoman for the Galicia region’s main court. At least 141 people were injured — some of them critically — after the eight-carriage train carrying 218 passengers derailed about an hour before sunset Wednesday night.

Authorities did not identify any possible causes of the accident on a pronounced curve just outside Santiago de Compostela, but a spokeswoman with Spain’s Interior Ministry said today that the possibility that the derailment was caused by a terrorist attack had been ruled out.

It was Spain’s deadliest train accident since 1972, when a train collided with a bus in southwestern Spain, killing 86 people and injuring 112. Prime Minister Mariano Rajoy, who was born in Santiago de Compostela, toured the crash scene today with rescue workers and then went to a hospital to visit injured passengers. Officials in the city canceled ceremonies for its annual religious festival that attracts tens of thousands of Christians from around the world.

“July 24 will no longer be the eve of a day of celebration but rather one commemorating one of the saddest days in the history of Galicia,” said Alberto Nunez Feijoo, president of the region of Galicia where Santiago de Compostela is the capital.

Rescue workers spent the night searching through smashed cars alongside the tracks, and Pardo said it was possible that the death toll could go higher. Many of the dead were taken to a makeshift morgue set up in the city’s largest indoor sports arena, where police and court officials were identifying the bodies.