Fires are continuing to burn near the French Riviera with new pockets of flames foiling the best efforts of crews to douse them.

Despite calmer winds and cooler weather, the fire that has forced thousands to flee and ravaged woodlands raged for a fourth day on Thursday, defying some 1,200 firefighters struggling to bring it under control.

The blaze, which has killed two people and injured 26, is the latest among numerous large wildfires to have scorched the Mediterranean region this summer.

The spokesman for the regional fire service, Florent Dossetti, called it one of the worst forest fires to hit southern France in centuries.

The fire has burned 8,100 hectares of forest since it started on Monday about 24 miles inland from the coastal resort of Saint-Tropez.

Several thousand people have been forced to evacuate campgrounds, hotels and homes across the region at the height of summer vacation in France.

Firefighters work at a wildfire near Le Luc (Daniel Cole/AP)
Firefighters work at a wildfire near Le Luc (Daniel Cole/AP)

In addition to chestnut, oak and pine trees, the blaze has consumed vineyards on the rolling hills of the low-lying Maures mountain range.

One family desperately shovelled dirt on flames in a vain attempt to protect their vines.

Smoke swept through wooded valleys as sirens wailed and the propellers on firefighting helicopters whipped overhead.

Earlier in the day, local authorities had said the fire was “less violent and its progression has slowed”.

Strong winds coming off the Mediterranean Sea that had fanned the flames calmed overnight.

High temperatures in the region, which had reached 40C (104F) in recent days, were dropping.

But new bursts of flames ignited in three spots Thursday, complicating firefighting efforts, Mr Dossetti said.

“We are working on drowning the edges (of the fire) to ensure it is extinguished, and to avoid new bursts of flames,” Mr Dossetti said.

A family which owns olive trees and a vineyard use shovels to put out flames near Le Luc (Daniel Cole/AP)
A family which owns olive trees and a vineyard use shovels to put out flames near Le Luc (Daniel Cole/AP)

The regional administration warned that the risk of new flames remained high, and kept several roads closed.

About 2,000 people evacuated from campgrounds earlier in the week were allowed to return, the administration said in a statement, though thousands of other evacuees remained housed in temporary shelters.

In the Gulf of Saint-Tropez, huge water-bombing planes could be seen swooping down to fill their bellies with water to dump across the flaming Riviera backcountry.

Reinforcements came in from elsewhere around France.

This summer has brought extreme heat, drought or wildfires to many parts of the world.

Scientists say there is little doubt that climate change from the burning of coal, oil and natural gas is driving such extreme weather events, and that the world will see more and more of them as the planet warms.

Wildfires this summer have left areas in Greece, Turkey, Italy, Algeria and Spain in smouldering ruins.

Firefighters at work (Daniel Cole/AP)
Firefighters at work (Daniel Cole/AP)

In Greece on Thursday, hundreds of Greek and Polish firefighters battled a major wildfire decimating a pine forest northwest of the Greek capital for a fourth day.

The fire near the village of Vilia, about 37 miles from Athens, has already burned through thousands of hectares, destroyed some homes and led to evacuation orders for several villages in the area. Strong winds forecast for later in the day could complicate firefighting efforts.

On the Croatian island of Hvar, a large fire that broke out overnight torched bushes, olive trees and some pine forests.

About 50 fire lorries and three firefighting planes were being used to control the blaze.