Spain is at “extreme risk” of new wildfires, the country’s prime minister has warned, as firefighters continue to battle 14 major blazes.

In a post on X, Pedro Sanchez said he expected Friday’s conditions to be “very tough again” as he posted a graphic from the national weather agency Aemet warning of extreme fire risk in the north and west of the country.

Temperatures are expected to reach as high as 40C on the Spanish north coast, after more than 1,500 sq km (579 sq miles) were devastated by the flames and seven people died.

A heatwave has scorched swathes of southeastern Europe this week, prompting wildfires in Spain, Portugal, Greece, France and the Balkans.

In Galicia, several fires merged to form a huge blaze, forcing the closure of highways and rail services to the region.

Avincis, the largest operator of emergency aerial services in Europe, said it had registered a 50% increase from last year in flight hours dedicated to firefighting operations in Spain and Portugal so far this season, Reuters reported.

Aemet forecasts the heatwave will continue until Monday, with temperatures of up to 44C in some areas, as well as moderate winds.

Wildfires are a common occurrence across southern Europe in the summer, but their severity can often be exacerbated by heatwave conditions.

Meteorologists say such extremes are becoming more frequent and intense due to human-induced climate change.

EU data shows that around 6,290 sq km (2,429 sq miles) of land has burnt across the bloc since the beginning of the year, with wildfires in Spain comprising about a quarter of the total.

Spain’s Civil Guard said it had arrested two men on suspicion of starting fires in Castille and León – taking the number of arson arrests to 10 since the start of June.

While weather conditions are currently favourable for wildfires, they can be sparked by barbecues, cigarette stubs or discarded bottles. Causing a wildfire is a criminal offence in Spain, even if accidental.

Spain is the fifth European nation to request assistance with fighting wildfires. In Greece, 100 sq km (38 sq miles) of land have burned since Tuesday.

On Friday, firefighters were still tackling an active front on the Greek island of Chios, three days after the blaze began, with repair teams warning it could take more than a week to restore damaged infrastructure. Much of the island is still without electricity, with some water supply issues reported in certain areas.

A very high wildfire risk has been issued for Friday for Attica, the Peloponnese, Central Greece, Thessaly, Central and Eastern Macedonia and Thrace, as well as the North and South Aegean, according to Greece’s Civil Protection agency.

Greece, Bulgaria, Montenegro and Albania have also activated the EU’s civil protection mechanism, which allows any country hit by a disaster – both in Europe and beyond – to request emergency assistance.

Additional reporting Nikos Papanikolaou