A Tracker firefighting aircraft crashed yesterday while battling a forest fire in the Ardeche region in southeastern France, killing its two pilots in the third such accident in a month, emergency services said.

"According to initial information, the aircraft crashed and exploded. Two Canadair (aircraft) came to help to put out the flames," said Patrick Duprat, head of the Ardeche prefecture's office.

According to a witness account cited by the prefecture, the Tracker's engine failed just before dropping its water cargo. Then it crashed and exploded on impact.

The accident follows the July 19 crash of another Tracker firefighting aircraft in the Var region in southern France in which the pilot escaped unhurt. On August 1 two Canadair pilots died when their firefighter crashed in Haute Corse, northern Corsica. The causes of the accidents are yet to be established.

The Trackers are made by US firm Grumman, now part of the Northrop Grumman Corp.

President Jacques Chirac and Interior Minister Nicolas Sarkozy sent their condolences to the families of yesterday's accident.

"This new appalling accident reminds us again of the heavy toll which firefighters, pilots and co-pilots of the civil safety planes pay each year in the fight against forest fires," Sarkozy said in a statement, urging vigilance on the part of the public to curb the outbreak of forest fires.