Governor Arnold Schwarzenegger: "Please listen and follow the evacuation orders"
Two firefighters have died in California as they battled intense wildfires to the north of Los Angeles.
The fires, fuelled by record temperatures, are now threatening over 12,000 buildings, officials say.
Residents of 10,000 homes have been told to evacuate. State Governor Arnold Schwarzenegger described the blazes as "still totally out of control".
The fires also threaten communication towers housing transmitters for all Los Angeles' major TV stations.
Mount Wilson near the city of Pasadena, where the towers are located, is also home to a historic solar observatory.
Firefighters are on the mountain clearing brush and spraying fire retardant in preparation for the fires, which are approaching the transmitters.
About 2,000 firefighters are trying to contain the fires, which have burnt over 66 sq miles (170 sq km) of forest.
'Did not listen'
County Deputy Fire Chief Mike Bryant said the two firefighters died when their vehicle rolled off a hillside near Mount Gleason in the Angeles National Forest on Sunday.
On Sunday, the wildfires rained ash on cars and homes as far away as central Los Angeles.
The fires were burning out of control in all directions, state officials said, but emergency crews were concentrating their efforts on the fast-moving northern edge of the inferno.
Mr Schwarzenegger, who declared a state of emergency last week, urged people to obey evacuation orders, after three people were badly burned.
"There were people that did not listen and there were three people that got burned and got critically injured because they did not listen," he said.
Two of those injured had been trying to shelter from the fires in a backyard hot tub.
Sheriff's spokesman Steve Whitmore said the pair, in Big Tujunga Canyon, "completely underestimated the fire" and the hot tub provided "no protection whatsoever".
Officials say the blaze is only 5% contained, with the area's steep, rugged hills making efforts to fight it more difficult.
Mandatory evacuation orders covering about 10,000 homes and 2,500 other buildings are in place.
Parts of Altadena, Glendale, Pasadena, La Crescenta are also affected.
Evacuation centres have been set up at local schools.
With forecasts of continuing hot weather, there has been speculation that it could take firefighters a week to bring the blaze under control, says the BBC's David Willis in Los Angeles.
Wildfires are a feature of the Californian summer, but it is unusual for them to break so close to major population centres.
A number of other fires are also burning in southern and central California.
A new fire in Placer County, northeast of the state capital Sacramento, destroyed 60 structures, many of them homes in the town of Auburn.