“We are facing something we have never seen. It is a real terrorist attack, it is coordinated actions,” Adrián Barbón, regional president of Asturias, tweeted on Friday.
Hundreds of people have been evacuated and several roads have been closed due to the fires.
Fires that have been going on for over a week in the eastern parts of the country are under control, the rescue service announces.
A prolonged drought prevails in Spain after three years of insufficient rainfall.