The death toll from a catastrophic high-speed train collision in southern Spain climbed to 40 on Monday as authorities launched a comprehensive probe into what officials described as an "extremely strange" disaster.

The accident, which occurred late Sunday near the Andalusian town of Adamuz, marks Spain’s deadliest rail tragedy since the 2013 Santiago de Compostela crash.

The incident unfolded when a Madrid-bound Iryo train originating from Malaga derailed on a straight section of track, veering into the path of an oncoming Renfe service headed toward Huelva.

Regional President Juan Manuel Moreno confirmed the updated fatality count during a press conference, noting that while 40 deaths are currently verified, the final figure may take up to 48 hours to confirm as heavy machinery continues to lift mangled wreckage to reach trapped victims.

Prime Minister Pedro Sanchez, who declared three days of national mourning during a visit to the crash site, promised "absolute transparency" in determining the cause of the tragedy.

Early reports from transport officials have deepened the mystery, noting that the Iryo locomotive was nearly new—last inspected just three days ago—and the track had been recently renovated.

Transport Minister Oscar Puente and Renfe President Alvaro Fernandez Heredia have largely ruled out human error and speeding, noting that both trains were operating at approximately 200 km/h, well below the 250 km/h safety limit for that corridor.

The impact left more than 120 people injured, with 41 passengers still hospitalized in Cordoba.

Survivors described a scene of "horror" characterized by shattering glass and a violent impact that threatened to collapse the carriages.

As rescuers and Guardia Civil units worked through the debris, the local community in Adamuz mobilized to provide water and blankets to those affected.

The international community, including Pope Leo XIV and French President Emmanuel Macron, has sent condolences to Spain as the nation grapples with the failure of its flagship high-speed rail infrastructure.