The record-breaking heat could endure for another week, experts warned, while Europeans scrambled to find respite in the sea, underground catacombs and the relative cool of night.

Europe, which has suffered Sahara-like weather that regularly topped 40 degrees Celsius (104 degrees Fahrenheit) over the past week "could see a drop in temperatures from August 15", said Dominique Escale, meteorologist for France's national weather service Meteo France.

In two weeks of an uninterrupted heat wave, the summer death toll has climbed to 39 in three countries.

Fast-moving fires in France and Portugal, kicked up by a deadly combination of drought, heat, human error and crime, have killed 20, while Spain on Saturday recorded its 19th death from heat-related illnesses when a 75-year-old woman died in a hospital of the southern province of Andalucia.

Firefighters have deployed in battalions of thousands, while high-risk forests are under soldiers' watch and zoo animals are being treated to frozen treats and fish trapped in ice cubes.

Meanwhile, blazes have ripped into chic French resort towns, parched Iberian brushland and even Croatian minefields -- all explosive situations triggering panic over the loss of life and livelihood alike.

Portuguese authorities said cooler nighttime temperatures and some humidity had helped reign in all but one of the wildfires, the worst on the continent and a national tragedy estimated to have cost the country a billion eurosbillion dollars).

But more than 2,000 firefighters, aided by some 800 soldiers, were still either battling existing fires or were monitoring forests for signs of new blazes, especially in light of possible electrical storms and continued high daytime temperatures.

Roughly 200,000 hectares (494,000 acres) of woodland have been lost to flames so far this year, most of it since July, according to the latest forest service estimate released on Friday.

In France, police arrested five people including a 17-year-old girl in connection with a blaze which destroyed three hectares of brush and trees on the outskirts of the southern Riviera resort of Nice overnight.

Scores of residents and tourists were evacuated from hillside villas east of the town, while Russian helicopters were brought in to douse the blaze before it was brought under control.

But two other fires sprung up on Saturday, some 30 kilometres (20 miles) northeast of Nice, where 1,600 hectares of brush and forest have already been consumed by the flames.

Thousands of others have been evacuated from the path of other fires in southern France and on the Mediterranean island of Corsica, amid the region's worst drought in a quarter of a century.

More than 10 wildfires were meanwhile still raging in Italy, where some 300 holidaymakers were evacuated overnight close to the southern city of Naples. Other fires were still out of control near Naples, as well as in the central province of Tuscany.

Croatia was also trying to tackle a blaze raging in its central Paklenica national park, Hina news agency reported.

But the task was doubly hazardous for firefighters: the near-inaccessible region still has not been swept for the landmines which were liberally planted there during the country's 1991-1995 war.

Europe's summer blazes have destroyed around 175,000 hectaresacres) of pinewood and brush, most of it in Portugal.

Europe's farmers are also suffering: producers in parts of the German state of Brandenburg said the heat could destroy up to 80 percent of their crops, while in France, about one million chickens have died this week.

Rising water temperatures forced German authorities to close a nuclear power plant and reduce output at two others.

In Romania, port authorities said the wrecks of two Nazi ships that sank in the Danube during World War II but recently resurfaced due to low water levels could block traffic on the river, one of Europe's longest waterways.

Nighttime swimming has become popular off Portugal's shores, where temperatures have topped 30 degrees Celsius after midnight. Spain's Mediterranean coast recorded a 45-year high, with a bath-like 32-degree waters this week near Catalonia.

And in Paris, tourists have fled into the Catacombs -- with their mean temperature of 15 degrees Celsius -- forcing authorities to turn people away because of a quota of only 1,000 visitors a day.

The heat wave has been caused by an anti-cyclone which has anchored itself firmly over the west European land mass, holding off rain-bearing depressions over the Atlantic and funnelling hot air north from Africa.

Although no clear evidence links the heat to global warming and greenhouse gas production, scientists at the World Meteorological Office point out that the world's 10 hottest recorded years have all taken place since 1987.

SPACE.WIRE