Some 1,700 firefighters were focusing their attention on a wide swathe of territory in the picturesque Maures hills of the Var region just off the French Riviera coast, near the fashionable resort town of Saint-Tropez.

By late afternoon authorities said the blazes -- which forced thousands to flee their homes -- had largely been brought under control, but firefighters battled to control one fire still raging near the town of Draguignan.

Water-carrying aircraft were deployed to help douse the fires, which broke out in force on Monday and have come during an exceptionally hot and dry summer in much of southern and central Europe.

For the first time, France was forced to call in foreign reinforcements. With Italian firefighters already on the scene, Paris also rented five water-dropping aircraft from Moscow, which headed to the zone on Tuesday.

Amid signs that some of the fires may have been started deliberately, Chirac said during a visit to French Polynesia that anyone found responsible would face "punishment of exceptional severity."

Visiting the region, Interior Minister Nicolas Sarkozy said Tuesday that authorities would "show no mercy to people who start fires, including those who do so out of carelessness", describing the blazes as an "ecological massacre".

"To be careless is to be criminal," Sarkozy warned.

Justice Minister Dominique Perben said identity checks would be carried out in high-risk areas in order to deter would-be arsonists.

Two British nationals -- identified as 63-year-old Margaret Timson and her 15-year-old granddaughter Kirsty Edgerton -- were found burned to death on Monday in woods outside the village of La Garde-Freinet.

A 76-year-old Dutch woman, whose body was found in the coastal town of Sainte-Maxime, and a 72-year-old Polish man were also killed, French officials said.

On the French Mediterranean island of Corsica, where brush fires also broke out on Monday near the southern town of Bonifacio, a 49-year-old man died after suffering severe burns while trying to save his home.

Dozens of houses were destroyed or damaged in the blazes and four firefighters were injured, one of them seriously, according to emergency workers.

On the French mainland some 6,500 residents and holidaymakers who were evacuated from Sainte-Maxime and surrounding towns were allowed to return home on Tuesday.

"The fires are criminal in origin," charged Elie Brun, the mayor of Frejus, who said officials had found Molotov cocktails apparently intended to set off fires.

Officials said the blazes had destroyed more than 8,000 hectaresacres) of woodland and brush in the Var region between the coastal cities of Marseille and Nice, most of it in the Maures hills.

More than 30,000 hectares of forest lands have burned in southeastern France and Corsica since the start of the summer, civil security officials said -- the most damage reported in the region in more than 25 years.

Last summer, only 4,250 hectares went up in flames in those areas.

"This couldn't have been an accident. It was real scum who did this," said Patrick Pauget, who was staying at a nearby campsite with his family until he was evacuated to a former military base in Frejus.

Peter Gordon, a German singer whose house in Sainte-Maxime was damaged by the flames, blamed holiday-makers: "Without a doubt, the campers with their barbecues sparked all this."

Eric Martin, head of the Var fire brigade, said efforts to combat the blaze were being hampered by the large number of isolated homes in the area, which were diverting manpower from the main front.

burs-bd/sst/sjw

TERRA.WIRE