At least 64 people have been killed in a collision between two trains in the Spanish province of Toledo.

The high-speed trains collided shortly before 9:15 a.m. local time (4:15 a.m. ET), when emergency services were deployed to the scene. It occurred on the Madrid to Seville line, with a stationary vehicle reportedly being hit by the other at a speed of over 100 kilometers per hour (62 miles per hour).

Authorities said they would open a local sports hall to help to those affected, with an Advanced Medical Post being set up at the site of the crash to triage the injured, provide medical care and transfer those requiring further treatment to hospitals. It is currently unclear how many people suffered injuries.

Railway infrastructure manager Adif is investigating the sequence of events surrounding the accident, Spanish news agency EFE reported on Wednesday.

Adif said in a post on X on Wednesday morning that traffic on the Madrid to Andalucía high-speed line had been interrupted.

The local Castilla La Mancha government confirmed at least 64 people had died, higher than another high-speed crash in southern Spain that killed 45 people earlier this year.

Officials currently do not know for certain what caused the collision. Government sources told El País that it appeared that an Adif operator made a mistake when railway signaling systems failed. The systems are automated, but they rely on manual operation when signals fail.

The trains were operated by AVE and Iryo, per local media. More than 500 passengers were on board the two trains, El País said.

Spanish Prime Minister Pedro Sanchez said in a post on X that he was "shocked" by the accident.

"Emergency services are working on the ground to assist those affected and ensure their safety, in coordination with all the involved administrations," he said, according to a translation. "My affection, solidarity, and support to all the victims and their families."

Sanchez's political future will be tested in a snap election next month, which he called following widespread unrest over Spain's housing crisis.

Santiago Abascal, leader of the far-right Vox party — which is expected to make gains when Spain goes to the polls — pointed the finger at Sanchez's government over the train accident on Wednesday.

"Tragedy again. Rage again over the neglect, the ruin, and the betrayal suffered by the Spanish people," he said in a post on X.

— CNBC's Charlotte Reed contributed to this article.