The collision occured in central Spanish province of Toledo, south of Madrid. Rail service is now suspended between Madrid, Ciudad Real and Andalusia.
Two trains collided south of Madrid on Wednesday morning, killing at least 10 people and leaving multiple others injured.
"The information we are receiving is not good at all. There are at least 10 dead and it is possible that the number will increase," a regional spokesperson told local media.
In a post on social media site X, Spanish Prime Minister Pedro Sánchez said he was "shocked" by the accident, and that he remained in contact with the transport minister and the Castilla-La Mancha autonomous community president.
Rail operator ADIF said in a social media post that the high-speed rail line from Madrid to the south had been suspended.
It was not immediately clear what caused the crash.
Our journalists are working on this story and will update it as soon as more information becomes available.