Four burned bodies found in the path of California's fierce wildfires raised the death toll to at least 12 people, even as firefighters won the upper hand and officials turned on Friday toward assessing the damage.

Though more than 20 fires raged across Southern California into a sixth day, some 8,000 firefighters had brought most of them under control and no more homes were in imminent danger.

Some lost everything to the flames but most of the 500,000 people forced to flee in California's largest evacuation were expected to be back in their homes by the weekend.

As officials began the massive clean-up and recovery operation, a risk firm said insured losses would likely be $900 million to $1.6 billion. Hot, dry winds had whipped up the string of fires but up to three are being treated as arson.

More than 60 people have been injured, many of them firefighters.

The Federal Emergency Management Agency, which along with President George W. Bush endured blistering criticism for the handling of Hurricane Katrina in 2005, had some 1,000 people on the ground across Southern California.

Local, state and federal agencies set up "one-stop" centers where Californians who lost their homes or property could apply for aid and get other services as they struggled to regain their footing.

Gov. Arnold Schwarzenegger, who toured the devastated areas with Bush on Thursday, has won praise for his handling of the fires, which he called "one of the worst disasters in California history."

As of Friday morning, the wildfires had blackened some 800 square miles of California and destroyed 2,000 homes and other structures. Losses were expected to top $1 billion in hard-hit San Diego County alone.

Bush, anxious to avoid the mistakes made with Katrina, and Schwarzenegger both vowed they would not desert those who had suffered in the fires.

BODIES IN RAVINE

Steve Conner, 62, whose home was one of 30 reduced to ruins on his block in suburban San Diego, described the moment he confronted the loss of his house and neighborhood.

"Emotionally, it was just beyond belief," the Vietnam War infantry veteran said, his voice shaking. "It's just totally wiped out. All the trees are black ... It just reminded me of Vietnam. It just reminded me of a war zone."

Late on Thursday, border patrol agents discovered four charred bodies in mountains near the Mexican border, bringing the probable death toll to 12.

The victims are thought to be illegal immigrants overrun by flames from the Harris fire as they walked through the rugged terrain. The remote area is often used by coyotes -- paid guides who smuggle people into the United States.

Agents found the remains, believed to be of three men and a woman, at the bottom of a rocky ravine east of San Diego and about 3 miles from the Mexican border.

"It seems fire-related," U.S. Border Patrol spokesman Matthew Johnson said. "The Harris fire at the border was out there."

California George W. Bush