“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,” said Prime Minister Mariano Rajoy in a written statement.
Seventy-three people were found dead at the scene of the accident and four died in hospitals, said Maria Pardo Rios, spokeswoman for the Galicia region's main court.
According to Yahoo! News, the disaster stirred memories of a train bombing in Madrid in 2004, carried out by Islamist militants, that killed 191 people.
This has been deemed one of the worst rail accidents in Europe in 25 years.