Several Americans are believed to have been injured in a high-speed train collision that killed at least 68 people in Spain on Wednesday when one train collided with another that had stopped on the tracks.

The crash took place in Spain's Castilla-La Mancha, with the regional government confirming the death toll and adding that another 58 people required medical treatment in hospitals. Several Americans are believed to have been hurt in the crash, according to the State Department.

Rescue workers continue to search in the wreckage for survivors and bodies, with witnesses describing a gruesome scene.

Wednesday's incident is the second high-speed rail crash Spain has suffered this year.

Spain’s rail system operator ADIF said the crash occurred Wednesday morning in the province of Toledo. Both trains were carrying hundreds of passengers, and were headed in the same direction on a route from Madrid to Seville.

One train, run by the state-owned RENFE company, ran into the tail of the other train owned by private company IRYO that had stopped, knocking two of its cars off the track. Those companies were the same ones involved in January's crash.

Esther Padilla, a spokesperson for the Castilla-La Mancha regional government, said 397 passengers were on the RENFE train and 147 passengers on the IRYO train.

Spanish Transport Minister Óscar Puente attributed the deadly train collision to what he described as an "inexplicable" decision by the country's central rail control center to allow a train to resume traveling after a safety system malfunctioned.

Puente said the train's engineers were not responsible for the collision.

According to Puente, a computer malfunction caused a safety system covering roughly 39 miles of track to stop working around 8:30 a.m.

The disruption forced trains in the affected area to stop, but the central control center subsequently authorized the RENFE train to resume traveling without speed restrictions, he said.

Just over 20 minutes later, the RENFE train collided with the stopped IRYO train.

Puente said the RENFE train should never have been cleared to resume traveling while a stop signal remained active on the line. At a minimum, he said, the train should have been instructed to proceed at a reduced speed.

Officials are still working to determine the train's speed at the time of the collision, but Puente said it may have been traveling at approximately 124 mph.

David Gómez, a construction worker, was working with his brother and another colleague nearby when they heard the crash and ran to help, he told the newspaper El País.

"People were trying to get out through the windows…. We cut through some fences to access the area and treated people with the first-aid kits we had brought," until emergency services arrived, he said. "As I was trying to pull a young woman out, there was a piece of a leg."

Spanish Health Minister Mónica García said emergency workers were focusing on rescuing survivors and bodies from the two most damaged train cars. She said the injured are being sent to different hospitals in the area.

"It was a high-speed impact, so we are expecting this to be a tragedy," García said.

Spanish Prime Minister Pedro Sánchez visited the crash site and announced that his government would declare three days of national mourning.

"Today all of Spain is grieving," Sánchez said.

The prime minister also called for enhanced safety measures across the country's rail system following the second high-speed rail crash this year.

"It is unacceptable for a country like Spain to suffer two high-speed rail accidents in the same year," he said.

Passenger Ignacio Relaño was traveling on the RENFE train. He told state broadcaster TVE that the train had stopped momentarily on the line before it started again and then crashed into the IRYO.

"We all felt the train abruptly slowing down and then the impact," he said. "The car leaned to one side like it was about to tip over. I hit my nose, everything went flying, luggage, cellphones. Everything shook."

Another passenger recounted to Cadena Ser radio how she felt the train slam on the brakes and was thrown forward in her seat, breaking the small table in front of her. She said she saw body parts and trapped people covered in blood.

IRYO, an Italian-owned company, said in a statement that it has "activated its security protocols and is closely working with authorities."

Spain’s King Felipe VI and Queen Letizia said in a short statement on X that they were following news of the accident.

"We are deeply saddened and concerned by the train accident in Urda (Toledo)," the royal couple said. "We share in the grief of the families and loved ones of those who lost their lives, and we send our heartfelt support to the injured and all those affected."

The Associated Press contributed to this report.