UPDATE: This horrific raw footage shows the moment when the train derailed at high speed.
The train, carrying more than 200 passengers, derailed on a curvy stretch of track near the city of Santiago de Compostela in the Galicia region on Wednesday.
The Renfe train was on a high-speed route between Madrid and Ferrol. The cause of the crash is unclear at this time.
Passenger Ricardo Montero said that "when the train reached that bend it began to flip over, many times, with some carriages ending up on top of others, leaving many people trapped below. We had to get under the carriages to get out."
Bodies of victims were pulled out of the train after the crash.
It was the country's deadliest rail incident since the 2004 Madrid bombing, which claimed 191 lives.
Rescuers helped the injured at the scene of the accident.
Bodies covered in blankets laid next to carriages turned on top of each other.
Rescue workers pulled victims from the train cars.
Spanish Prime Minister Mariano Rajoy offered his condolences to the victims.
"In the face of a tragedy such as just happened in Santiago de Compostela on the eve of its big day, I can only express my deepest sympathy as a Spaniard and a Galician," he said in a statement.
Video from the aftermath of the train accident in Spain:
President Obama released the following statement Thursday expressing his condolences on behalf of the U.S., and offering assistance.
Michelle and I were shocked and saddened by the news of yesterday's tragic train derailment in Santiago de Compostela, Spain. On behalf of the American people, we offer our deepest sympathies and condolences to the families and loved ones of the more than 80 people who lost their lives. We extend our wishes for a full recovery to those who were hurt. We also offer our heartfelt gratitude to the Government of Spain and to the rescue personnel who are working to locate the missing and treat the injured – including at least six Americans. Today the American people grieve with our Spanish friends, who are in our thoughts and prayers. We stand ready to provide any assistance we can in the difficult days ahead.