Raging wildfires in Spain have spread to the southern slopes of the Picos de Europa mountain range and authorities closed part of the popular Camino de Santiago pilgrimage route.

About 20 wildfires, fuelled by a severe 16-day heatwave, have devastated more than 115,000 hectares in the regions of Galicia and Castile and Leon over the past week.

“This is a fire situation we haven’t experienced in 20 years,” Defence Minister Margarita Robles told radio station Cadena SER. “The fires have special characteristics as a result of climate change and this huge heatwave.”

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She said thick smoke was affecting the work of water-carrying helicopters and aircraft.

The Spanish army has deployed 1900 troops to help firefighters.

Highways and rail services have been cut in the area, as well as the Camino de Santiago hiking route, an ancient pilgrimage path trodden by thousands in the summer.

It links France and the city of Santiago de Compostela on the Western tip of Spain, where the remains of the apostle St James are said to be buried.

Authorities in the Castile and Leon region have closed the path in the area between the towns of Astorga and Ponferrada, which are about 50 kilometres apart, and told hikers “not to put lives in danger”.

A firefighter died when his truck crashed on a forest path near the village of Espinoso de Compludo. Four firefighters have died so far.

The interior ministry says 27 people have been arrested and 92 are under investigation for suspected arson since June.

Southern Europe is experiencing one of its worst wildfire seasons in two decades, with Spain among the hardest-hit countries.

In Portugal, wildfires have burnt 155,000ha so far in 2025, according to the ICNF forestry protection institute — three times the average for this period between 2006 and 2024. About half of that area burned in the past three days.

Robles said things are not likely to improve until the heatwave that has seen temperatures hit 45C starts easing on Monday evening or Tuesday.

The heatwave is the third-hottest since 1975, when the national weather agency started tracking them. Most of the nation is subject to wildfire warnings.