LOS ANGELES - Two massive wildfires menacing Los Angeles from the east and west devoured nearly 10,000 homes and other structures, burning into a third night on Thursday even as the fierce winds eased and gave firefighters a welcome but temporary respite.

The Palisades Fire between Santa Monica and Malibu on the city's western flank and the Eaton Fire in the east near Pasadena already rank as the most destructive in Los Angeles history, consuming 34,000 acres (13,750 hectares) - or some 53 square miles - turning entire neighborhoods to ash.

Officials from three different jurisdictions reported a total of seven people dead, though Los Angeles County Sheriff Robert Luna told a press conference he did not want to pronounce an exact number until it was safe for human remains detection teams to conduct house-to-house searches.

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But based on the widespread devastation, he expected the number to grow.

"It looks like an atomic bomb dropped in these areas. I don't expect good news, and we're not looking forward to those numbers," Luna said.

Earlier, he reported the Eaton Fire alone had damaged or destroyed 4,000 to 5,000 structures. Officials said the Palisades Fire destroyed another 5,300 structures.

Private forecaster AccuWeather estimated the damage and economic loss at $135 billion to $150 billion, portending an arduous recovery and soaring homeowners' insurance costs.

"We're already looking ahead to aggressively rebuild the city of Los Angeles," said Mayor Karen Bass, a Democrat, who faced criticism from President-elect Donald Trump and other Republicans over her handling of the disaster.

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President Joe Biden, who declared a major disaster on Tuesday, promised on Thursday that the federal government would reimburse 100% of the recovery for the next 180 days to pay for debris and hazard material removal, temporary shelters and first responder salaries.

"I told the governor, local officials, spare no expense to do what they need to do and contain these fires," Biden said after meeting with senior advisers at the White House.

In all, five wildfires burned in Los Angeles county, and the skies buzzed with aircraft dropping retardant and water on the flaming hills.

One rapidly growing blaze broke out on Thursday near Calabasas, one of the wealthiest cities in the US and home to numerous celebrities and gated communities. The so-called Kenneth Fire expanded to 960 acres (388 hectares) in a matter of hours.

With nerves on edge, Los Angeles county mistakenly sent an evacuation notice countywide to a population of 9.6 million, even though it had been meant only for the area of the Kenneth Fire, officials said. A correction was quickly sent.

'We are alive'

Some Pacific Palisades residents ventured back to areas the fire had already swept through, where brick chimneys were left looming over charred waste and burnt-out vehicles.

"We are alive. That's all that matters," private security guard Bilal Tukhi said while standing watch outside his employer's damaged home, saying the scene reminded him of his native, war-torn Afghanistan.

School was canceled for a second day on Friday due to the smoke, ash and particulates that contaminated the air, Superintendent Alberto Carvalho said.

The Eaton Fire's growth has been significantly stopped, Marrone said, though it remains 0 percent contained. While still strong, winds have diminished since the 100-mile-per-hour (160-kph) gusts seen earlier in the week, permitting crucial aerial support for crews on the ground.

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But officials warned that the wind was forecast to intensify again overnight, and red flag conditions were expected until Friday afternoon.

The Eaton Fire reached the grounds of the Mount Wilson Observatory, the place where a century ago Edwin Hubble discovered the existence of galaxies beyond the Milky Way and that the universe is expanding.

"We are relieved to report that the flare-up of the Eaton Fire near the Observatory seems to be under control for now," the observatory said in a statement.

The two biggest conflagrations - the Palisades and Eaton fires - formed a pincer around the city so enormous that it was visible from space.

In Pacific Palisades, an upscale and picturesque enclave where many celebrities reside, once-palatial homes stood in ruins, while downed power lines and abandoned cars littered the roadways. The smell of heavy smoke filled the air, and residents wearing masks rode bicycles, hoping to catch a glimpse of their damaged houses.

Aerial video showed block after block of leveled homes, while satellite images showed the two largest fires forming a pincer around the city and thick plumes of smoke from the fires being blown out over the Pacific Ocean.

Hollywood fire contained

Firefighting crews managed to fully control the Sunset Fire that forced mandatory evacuations in Hollywood and Hollywood Hills, after flames had raged atop the ridge overlooking Hollywood Boulevard's Walk of Fame on Wednesday night and fleeing residents created a traffic jam.

The homes of movie stars and celebrities were among those consumed by flames.

Chef Jose Andres, the Spaniard known for providing free food to disaster victims around the world, set up a food truck near the Palisades Fire on Pacific Coast Highway.

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"Everybody needs support and love in these moments, wealthy or not, poor or not," he said.

Actor Jamie Lee Curtis said on Thursday her family would donate $1 million to relief efforts.

Firefighters from half a dozen other US states and Canada were being rushed to California, in addition to US federal personnel and materiel.

"To our American neighbours: Canada's here to help," said Canadian Prime Minister Justin Trudeau, whose country has experienced its own severe wildfires.