Los Angeles: The two biggest wildfires ravaging the Los Angeles area have killed 10 people so far and burned at least 10,000 homes, buildings and other structures, officials said Thursday as they urged more people to heed evacuation orders after a new blaze ignited and quickly grew.

The fast-moving Kenneth Fire started in the late afternoon in the San Fernando Valley just 3.2 km from a school serving as a shelter for fire evacuees and then moved into neighbouring Ventura County .

Only hours earlier officials expressed encouragement after firefighters aided by calmer winds and help from crews from outside the state saw the first signs of successfully beating back the region's devastating wildfires that have killed 10 people so far.