Around 400 people were displaced in and around the town of Carucedo, and another 700 from several towns near the UNESCO World Heritage Site of Las Medulas, a former Roman gold-mining area known for its striking red landscape, local officials said.

The head of the regional government of Castile and Leon, Alfonso Manueco, said experts suspect several of the blazes were set by arsonists.

"We will be relentless with the perpetrators of these attacks against the lives and safety of people and our historical and natural heritage," he wrote on X.

Spain's Military Emergency Unit (UME) has deployed nearly 60 soldiers and 20 vehicles to the area, joining a large firefighting operation that includes aircraft and bulldozers working to create firebreaks.

Firefighters said scorching temperatures, low air humidity levels and strong winds which often changed direction were complicating their efforts to put out the flames.

Wildfires were also affecting the northern regions of Galicia and Navarre as Spain endures a heatwave which is entering its second week, with temperatures nearing 40 degrees Celsius (104 Fahrenheit) in many regions.

The extreme heat is expected to last until at least Thursday. Civil protection authorities have warned of a high to extreme wildfire risk across much of the country.

Spanish Prime Minister Pedro Sanchez wrote on X that he was "closely following the wildfires", and thanked emergency teams "for their tireless efforts."