A high-speed train derailed, jumped onto the track in the opposite direction and slammed into an oncoming train Sunday in southern Spain, killing at least 39 people and injuring dozens more, officials said, writes NBC NEWS.

The tail end of an evening train traveling from Malaga to Madrid with some 300 passengers went off the rails near Córdoba at 7:45 p.m. local time. It slammed into a train coming from Madrid to Huelva, another southern Spanish city, according to rail operator Adif.

Spain’s Civil Guard updated the death toll to at least 39 people early Monday.

Rescue efforts were still underway Monday morning. Andalusia regional President Juanma Moreno said 75 passengers were hospitalized, with most taken to Cordoba, about 242 miles south of Madrid. The Spanish Red Cross set up a help center in the town of Adamuz, near the crash site, offering assistance to emergency services and people seeking information. Members of Spain’s civil guard and civil defense worked on site throughout the night.

Spain’s Transport Minister Óscar Puente early Monday said the cause of the crash was unknown.

He called it “a truly strange” incident because it happened on a flat stretch of track that had been renovated in May. He also said the train that jumped the track was less than 4 years old. That train belonged to the private company Iryo, while the second train, which took the brunt of the impact, was part of Spain’s public train company Renfe.

According to Puente, the back part of the first train derailed and crashed into the head of the other train, knocking its first two carriages off the track and down a 4-meter slope. He said the worst damage was to the front section of the Renfe train.