By April Lanux

Firefighters are making an all-out assault to prevent the largest of the deadly wildfires that is threatening Los Angeles from spreading into one of the city's most exclusive neighbourhoods.

Aerial crews have been bombarding the flaming hills with water and fire retardant to hold back the Palisades fire, which has expanded an additional 1,000 acres and is now menacing Brentwood.

Officials have been on the defensive amid mounting anger at how hydrants ran dry as firefighters struggled to contain the fast-moving blazes.

Winds are expected to pick up again overnight, further fanning the flames that have already left at least 11 people dead.

"LA County had another night of unimaginable terror and heartbreak," said Los Angeles County Supervisor Lindsey Horvath on Saturday.

Firefighters have made modest progress against the worst of the infernos, the Palisades fire, which has scorched nearly 23,000 acres and is 11% contained.

But the conflagration has spread into the Mandeville Canyon neighbourhood, sparking evacuation orders for swathes of Brentwood, a ritzy enclave where Arnold Schwarzenegger, Disney chief executive Bob Iger and NBA star LeBron James have homes.

Also in the evacuation zone is the Getty Center, a hilltop museum that holds more than 125,000 artworks, including masterpieces by Van Gogh, Rembrandt, Rubens, Monet and Degas. The building is undamaged so far.

The second-biggest blaze, the Eaton fire, has razed more than 14,000 acres and was 15% contained. Firefighters have mostly contained two smaller blazes, the Kenneth and Hurst fires.

But the National Weather Service warned that the gusty Santa Ana winds that whipped up the fires at the outset would increase again on Saturday and into Sunday.

Seven neighbouring states, the federal government and Canada and Mexico have rushed resources to California.

No cause has yet been established for the fires. The two biggest ones combined have razed an area more than twice the size of Manhattan.

Some 153,000 residents are under mandatory evacuation orders and another 166,000 have been warned they may have to flee, too.

The political repercussions have begun.

On Friday, Governor Gavin Newsom, a Democrat with rumored White House aspirations, ordered an investigation into why a key reservoir was out of service and some fire hydrants ran dry.

Los Angeles Fire Chief Kristin Crowley complained about the shortage.

"When a firefighter comes up to a hydrant, we expect there's going to be water," she said.

Chief Crowley has also attacked city leadership for cutting her department's budget and eliminating mechanic positions, which she said had resulted in more than 100 fire apparatuses being out of service.

On Saturday, Los Angeles Mayor Karen Bass - who has been criticised for being in Ghana attending the inauguration of the African country's president when the fires erupted in LA on Tuesday, hinted at her tensions with Chief Crowley.

"Let me be clear about something," Bass told a news conference, "the fire chief and I are focused on fighting these fires and saving lives, and any differences that we might have will be worked out in private."

More than 70,000 people have signed a change.org petition demanding the mayor's immediate resignation.

As fears of looting grow, a sunset-to-sunrise curfew is being strictly enforced effect in evacuated areas, official said.

Newsom announced on Saturday that he would double the number of National Guard on the ground to "keep communities safe", deploying 1,680 troops.

About two dozen arrests have been made, including for burglary, looting and curfew violations.

Los Angeles County Sheriff Robert Luna said cadaver dogs are helping 40 search and rescue team scour razed neighbourhoods.

The death toll is expected to rise once house-to-house searches are conducted.

The fires were so intense that wheel alloys on cars were melted to puddles of liquid metal.

Rick McGeagh, an estate agent, told Reuters news agency that in his Pacific Palisades neighbourhood only six out of 60 homes survived.

All that remained standing at his house was a statue of the Virgin Mary.

"Everything else is ash and rubble," said the 61-year-old father-of-three.