More than 1,000 firefighters are battling a “monster” wildfire in south-western France that has already destroyed nearly 7,000 hectares (17,300 acres) of forest, officials say.
The raging blaze near the city of Bordeaux has gutted a number of homes and forced 10,000 residents to flee.
“It’s an ogre, it’s a monster,” firefighter representative Gregory Allione told France’s RTL Radio.
Strong winds and high temperatures are hampering the firefighting operation.
President Emmanuel Macron announced that Austria, Germany, Greece, Poland and Romania “are coming to aid” France in battling the blaze. “European solidarity at work!” he tweeted.
This summer France and a number of other European countries have seen a wave of deadly wildfires, triggered by record temperatures and droughts across the continent.
More than 1,000 deaths have been attributed to the heat in Portugal and Spain.
In the UK, an amber extreme heat warning has now come into force, with temperatures forecast to hit 37C (99F) in some areas over the next four days. The heatwave will probably affect health, transport and working conditions, the authorities warn.
The huge wildfire in France’s Gironde region has been raging for two days near the commune of Landiras, about 30km (19 miles) south-east of Bordeaux.
A number of firefighters have had to be urgently redeployed from other regions to boost the ongoing operation.
They are being backed by specialist aircraft that have been dropping water and flame retardant.
But despite all the efforts, the blaze was still out of control on Thursday, local officials said.
“It’s the first time we’ve seen a fire like this,” French firefighter Jérôme Jean told BFMTV news website.
Before the evacuation, some of the local residents had to save themselves on rooftops as the flames rapidly approached their houses, reports say.
Belin-Béliet is now a ghost town since all of its 2,000 inhabitants had to flee on Wednesday, BFMTV says.
In nearby Hostens, Allisson Fayol and her father – unlike many of their neighbours – decided to stay at home for now.
“There is still a lot of smoke but for now it’s not coming this way,” Ms Fayol was quoted as saying by Reuters news agency.
Temperatures are expected to reach as high as 39C later on Thursday.
Prime Minister Elisabeth Borne and Interior Minister Gérald Darmanin have arrived to the affected area to inspect the scale of the damage.
Climate change increases the risk of the hot, dry weather that is likely to fuel wildfires.
The world has already warmed by about 1.2C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.