Basque weather agency Euskalmet on Thursday raised the wildfire risk in the region to moderate and high, depending on the area.
"We have an orange alert today, Saturday and Sunday are also expected to have an orange alert for forest fires," firefighter Jon Sanchez told Reuters as he took a break from battling the blaze in Sopela, in the Basque province of Biscay.
Several brutal heatwaves with spikes well above 40C (104F) hit southern Europe during the summer, part of a global pattern of rising temperatures, widely attributed by scientists and climatologists to human activity.
Government figures indicate this year has been the worst year for wildfires in Spain with 260,000 hectares (642,500 acres) destroyed by blazes.
Throughout Europe, wildfires have burned 775,941 hectares this year, the second-largest area on record, according to data from the European Union's Joint Research Centre.
