Firefighters | die in Los Angeles wildfires

Two firefighters have died and a major telecommunications centre is under threat from the huge wildfires raging out of control in the hills above Los Angeles.

As the fire, fuelled by high temperatures, low humidity and tinder dry forests continued to spread in all directions, California governor Arnold Schwarzenegger urged residents to obey evacuation orders for the "very dangerous" blaze that has already burned through 42,000 acres and is threatening 12000 homes.

The two firemen were in the midst of an intense fire in the Angeles National Forest on Sunday afternoon when their fire engine rolled off the mountainside, according to county deputy Fire Chief Mike Bryant.

He did not give a cause for the crash.

As ash fell as far away as central Los Angeles, fire fighters focussed their attention on Mt Wilson, the site of 22 transmission towers for television and radio broacasts as well as emergency services. Officials said the flames could be on the towers within hours, as planes dumped tons of water in the area and 2500 firemen contiued to build 100 miles of fire protection lines.

The 100-year-old Mt Wilson Observatory, a major centre for astronomy and home to several university programmes, is also under threat.

So far, at least 18 buildings have been destroyed, and three people have been burned including a couple who tried to ride out the fire in their backyard hot tub.

Sheriff's spokesman Steve Whitmore said the pair "completely underestimated the fire" and the hot tub provided "no protection whatsoever".

The fire, which stated on Wednesday, is still only five percent contained and officials said that, with high temperatures and low humidity, it was only going to get bigger.

Although a lack of high winds has helped limit the spread of the fires it has also made it hard to fight them from the air as thick smoke is building up over the flames instead of being blown away, said Mr Schwarzenegger.

The areas affected by the blaze include foothill suburbs such as Big Tujunga Canyon, La Canada Flintridge, Glendale, and Altadena.

Another wildfire is also raging near Los Angeles in the San Bernardino National Forest.