Iryo said its train, which had 147 passengers on board, was “struck from behind” by another train, by Renfe train which was carrying 397 passengers.

Spain’s transport minister Óscar Puente said on Wednesday that the decision to instruct the trains to move again, without any speed restrictions, was “inexplicable”.

Prime Minister Pedro Sánchez said the “whole of Spain is grieving”, adding that “lives have been shattered, families have been torn apart, the pain is immense”.

Emergency crews worked through the night under powerful floodlights to cut open metal carriages in the search for victims, with many of those killed in the crash still to be identified.

Hundreds of personnel have been deployed to the disaster site to assist with recovery efforts, according to Spain’s interior ministry, with drones and helicopters being used to find victims and remove rubble.

Witnesses described seeing people crying and bleeding, passengers trapped in their seats and smoke billowing throughout the carriages, one of which caught fire.

Sánchez said it was “unacceptable” that Spain had suffered two serious rail disasters this year, after a high-speed crash killed 46 people near Córdoba in January. It occurred on the same line as Wednesday’s accident, but much further south.

Most political parties suspended campaigning for upcoming elections following the incident.

The exception was the far-right party Vox. Its leader, Santiago Abascal, said his party would not take part in what he described as attempts to “use mourning to silence criticism” of the country’s rail infrastructure.