Alberto Nunez Feijoo, head of the regional government in Galicia, declared seven days of mourning in the region for victims of the tragedy.
In a speech, he said "all of the community cries about the tragedy that we are living, we cry for the victims, we cry for the unease and sadness of the families."
Spanish Prime Minister Mariano Rajoy viewed the scene of devastation and visited some of the hospitalized crash victims Thursday.
Rajoy, who is from Santiago de Compostela, said two investigations are under way. "We want to establish what happened," he said.
The prime minister declared three days of national mourning to honor the victims of the crash.
The crash came on the eve of a public holiday to celebrate a saint's day, when more people than usual may have been traveling in the region. Planned festivities in Santiago de Compostela and across Galicia were canceled after the crash.