LOS ANGELES, Oct 24: Fires raged across California for a fourth day on Wednesday as officials said property worth one billion dollars had been lost and President George Bush declared the region a major disaster zone.

Around 1,700 buildings have been reduced to charred rubble in 18 fires that have erupted since Sunday, forcing an estimated 500,000 people to flee their homes and scorching 172,000 hectares of tinder-dry countryside from celebrity-studded Malibu to beyond the Mexican border.

California Governor Arnold Schwarzenegger said three people had died and 40 people had been injured in the fires, which are the worst to hit California since devastating 2003 blazes which claimed the lives of 22 people.

So far 1,664 structures, including 1,436 homes, have been destroyed while a further 25,000 buildings remained threatened, Schwarzenegger added.

The fast-spreading infernos have been fuelled by hot desert winds gusting across the region, making conditions hazardous for thousands of exhausted fire-fighters who have been tackling the flames relentlessly.

Although the winds subsided slightly on Wednesday, fire-fighters said they were struggling to keep pace with the Hydra-like firestorm, which has stretched resources to breaking point.

President Bush formally declared the region a disaster zone, paving the way for federal funds to boost the relief effort.

“Today I’ve signed a major disaster declaration which will then enable federal funds to start headed towards the families who have been affected by these fires,” said Bush, who is to tour California on Thursday.

Some 8,900 fire-fighters -- including 2,600 prison inmates trained to tackle fires -- are battling the flames supported by 90 firefighting aircraft, including a DC-10, 25 air tankers and 40 helicopters.

Schwarzenegger, who has described the destruction as “terrible and tragic,” meanwhile paid tribute to the weary legions of fire-fighters, some of whom had been working non-stop for days.

“They are really extraordinary, they are working 24 hours a day, around-the-clock. In fact many of them have been working 36 or 48 hours without stopping,” Schwarzenegger said.

A spokeswoman for San Diego County said the total cost of fire damage had exceeded one billion dollars and was expected to go higher. The figure did not include losses sustained by business and commerce.

“So far the costs across the San Diego County region are estimated at just over on billion dollars and we expect that to increase,” Lesley Kirk, a spokeswoman for San Diego County, said.

The costs were calculated solely on the basis of property destroyed, Kirk said. San Diego has emerged as the ground zero of the crisis, where the bulk of hundreds of thousands of evacuations have taken place.

Some 12,000 evacuees spent the night at Qualcomm Stadium, home of the San Diego Chargers American football team. By early today local media reported 7,500 people remained at the facility as evacuation orders began to be lifted.

A total of 318,000 households had been ordered evacuated in San Diego alone, where officials have put the numbers of displaced people at 500,000.

A spokeswoman from the California Governor’s Office stressed that exact figures for the numbers of evacuees were hard to pin down, and would not comment on estimates that the state-wide total could be closer to 900,000.—AFP