At least 21 people were killed after a high-speed train derailed and crashed into an oncoming train in southern Spain on Sunday evening, pushing the second train off the tracks and down a railway embankment, authorities said.

The accident occurred near Adamuz in the province of Cordoba, about 360 kilometres south of Madrid, Spain’s Interior Ministry confirmed.

Andalucia regional government chief Juanma Moreno said 75 people were hospitalised, with 15 in serious condition. He warned that the death toll could rise as rescue operations continued.

“The force of the accident has been very strong… we will likely find more bodies,” Moreno told reporters early Monday, adding that heavy machinery would be required to remove twisted metal from the wreckage.

The crash happened at around 7:45 pm (1845 GMT), roughly 10 minutes after an Iryo-operated high-speed train travelling from Malaga to Madrid departed Cordoba. According to rail infrastructure operator Adif, the Iryo train derailed at Adamuz and crashed onto an adjacent track, where it struck a Renfe Alvia train travelling from Madrid to Huelva.

The impact caused the Renfe train, which was travelling at about 200 kilometres per hour, to derail and plunge down an embankment. It remains unclear how fast the Iryo train was travelling at the time of the derailment.

Spanish Transport Minister Oscar Puente said the cause of the crash was not yet known, calling it “really strange” that a derailment occurred on a straight section of track that had been renewed in May.

Most of the fatalities and serious injuries were in the first two carriages of the Renfe train, Puente said. The first carriage had 37 passengers and the second had 16.

There were around 400 passengers on the two trains combined — more than 300 on the Iryo service and about 100 on the Renfe train. Most were Spaniards travelling to and from Madrid after the weekend.

Video footage shared on social media showed rescuers pulling passengers from overturned and twisted carriages under floodlights, while others climbed out through smashed windows. Some injured passengers were carried away on stretchers.

El Pais newspaper reported that the 27-year-old driver of the Renfe train was among those killed.

Fire chief Paco Carmona of Cordoba said the Iryo train was evacuated within hours, but the Renfe carriages were severely damaged, with people still trapped inside.

“There are still people trapped. The operation is focusing on very narrow areas,” he told state broadcaster TVE. “It is a complicated task.”

Prime Minister Pedro Sanchez said Spain was experiencing “a night of deep pain,” while a royal palace spokesperson said King Felipe and Queen Letizia were following developments with concern.

Iryo, a private rail operator majority-owned by Italy’s state-controlled Ferrovie dello Stato, said it deeply regretted the incident and had activated emergency protocols. Renfe said its train derailed after the Iryo train entered its path and that it was supporting victims and their families.

Rail services between Madrid and Andalucia have been suspended as investigations continue.