Over 10,000 people have fled their homes as a massive wildfire in California continues to spread.

The so-called Station Fire is burning through mountains north of Los Angeles and threatening Mount Wilson, a major broadcasting hub.

Fire officials say at least 71 homes have been destroyed since the blaze erupted last Wednesday - 53 clustered in the foothill community of La Crescenta on the northern fringe of suburban Los Angeles.

As of Monday evening, a total of 6,300 homes throughout the fire zone were under evacuation orders, authorities said.

Two firefighters died on Sunday when they were overrun by flames in the Angeles National Forest and rugged San Gabriel Mountains.

More than 3,655 firefighters are battling the nearly week-old fire in the Angeles National Forest, which has sent a huge mushroom cloud of smoke east toward Las Vegas.

A squadron of aircraft, including eight air tankers and 13 helicopters, have been deployed to bombard the blaze with fire-retarding chemicals, although vast plumes of smoke are hampering the aerial attack.

With no forecast for an immediate break in the triple-digit temperatures and very low humidity, officials have pushed back their projected date for full containment of the blaze by one week to 15 September.

‘This is a very angry fire that we're fighting right now,’ Fire Commander Mike Dietrich told a news conference. ‘Until we get a change in the weather, I'm not overly optimistic.’

Crews battle to protect Mount Wilson

Fire crews are fighting to protect the slopes around the 1,740-metre peak of Mount Wilson, home to 50 buildings plus a famous array of telescopes and a critical cluster of transmission towers emergency services and broadcasters.

After dousing the area in fire retardant and labouring to clear brush away from structures on the site, they fell back early yesterday to avoid flames expected to sweep the summit.

The fire threat has eased in some foothill communities that were menaced over the weekend. Other neighbourhoods are now at risk, including about 300 homes on the southwest flank of the blaze just inside Los Angeles city limits.

Schwarzenegger visits fire damaged site

Arnold ScharzeneggerThe blaze is being fuelled by dense, tinder-dry vegetation that had not burned in decades. So far, the Santa Ana winds - which have fanned many of Southern California's worst wildfires in recent years - have been absent.

Governor Arnold Schwarzenegger earlier toured the scene of a fire in Placer County, northeast of Sacramento, that has charred 110 hectares of forest and gutted some 50 homes.

Schwarzenegger urged residents who received an evacuation order to flee immediately.

'I think the key thing is when you hear from law enforcement, anything about evacuation, follow their orders, Mr Schwarzenegger said.