At least 21 people have died and dozens more were injured in a train collision in southern Spain, with authorities warning the death toll could rise in the country’s deadliest rail accident in over a decade.

A Madrid-bound train derailed and crossed onto the opposite track, colliding with an oncoming train in Adamuz, near Córdoba.

Both trains were carrying around 400 passengers and staff, according to the rail network.

Andalusia’s emergency services reported that at least 24 people, including four children, sustained serious injuries.

Spanish Transport Minister Óscar Puente called the crash “extremely strange” as authorities opened an investigation into the incident.

All the railway experts consulted by the government are extremely baffled by the accident,” Puente told reporters in Madrid.

Rail network operator Adif said the collision occurred about ten minutes after the train departed Malaga at 18:40 local time (17:40 GMT) for Madrid, after derailing on a straight section of track.

The impact pushed the carriages of the oncoming train into an embankment, Puente said, noting that most of the fatalities and injuries were in the front carriages of that train.

Rescue teams said the twisted wreckage of the trains made it challenging to reach and recover people trapped inside the carriages.

Salvador Jimenez, a journalist with RTVE who was on one of the trains, described the impact as feeling like an “earthquake.”

“I was in the first carriage. There was a moment when it felt like an earthquake and the train had indeed derailed,” Jimenez said.