The forest fire north of Zaragoza started on Wednesday and is spreading, local authorities say.
Hot, dry winds are feared to fan the flames again in parts of the forest where the fire has died down, according to Roberto Bermudez de Castro, head of security at the regional government of Aragon.
"What worries us the most is the wind, which is changing rapidly. There will be absolutely crazy winds over the next 24 hours," he says.
More than 400 firefighters, backed by the military, and more than 30 firefighting aircraft are battling the flames. Several smaller villages in the area have been evacuated.
Last week, 13 people died in a forest fire in Almería, in Spain's southern region of Andalusia.
