At least 39 people were killed when two high-speed trains collided in southern Spain on Sunday night, marking the country’s deadliest rail disaster in more than a decade and prompting an urgent safety investigation.

The crash occurred near the town of Adamuz in Córdoba province, when a Madrid-bound high-speed train derailed on a straight section of track, crossed into the opposite line and slammed into another train travelling south from Madrid to Huelva, according to Spain’s Civil Guard.

Around 400 passengers and crew were onboard the two trains. Emergency services treated 122 people, with 43 remaining hospitalised, including four children. Thirteen people are in intensive care, officials said.

Spain’s Transport Minister Óscar Puente warned the death toll could rise, calling the incident “extremely strange” and saying railway experts were struggling to explain how a derailment occurred on a straight stretch of track.

The force of the collision sent carriages crashing into an embankment. Authorities said most fatalities were concentrated in the front carriages of the second train, while twisted metal and crushed compartments complicated rescue efforts. Firefighters were forced to remove bodies to reach trapped survivors.

A journalist travelling on one of the trains described the impact as feeling like “an earthquake.” Passengers reported screaming, darkness and confusion, with desperate calls for doctors echoing through damaged carriages.

All rail services between Madrid and Andalusia have been suspended, and emergency medical posts were set up near the crash site to treat the injured and assist families awaiting news.

Prime Minister Pedro Sánchez said Spain was enduring “a night of deep pain,” as condolences poured in from across Europe, including messages from King Felipe VI and Queen Letizia.

An official investigation is under way, though authorities say it may take at least a month to determine the cause.

Spain operates the second-largest high-speed rail network in the world, spanning more than 4,000 kilometres. The crash has raised urgent questions about rail safety on one of Europe’s busiest transport corridors.