Thousands of people in California have left their homes as a wildfire threatens the town of Santa Barbara.

The rapidly-moving blaze has burned over 1 000 hectares, leading California Governor Arnold Schwarzenegger to declare a state of emergency.

The fire is proving extremely difficult to bring under control, the governor said during a tour of the area, cited by the BBC.

More than 70 homes have been damaged and some 15 000 residents evacuated as the blaze continues for a third day.

A further 3 500 homes remain threatened and thousands more residents are being told to get ready to leave, officials say.

At least 10 firefighters have been injured, three seriously, in the blaze which is being investigated as possible arson. Santa Barbara, with its idyllic climate and lush countryside, is often referred to as the American Riviera.

Since Wednesday, the fire has moved ever nearer to the seaside town.

TV pictures have shown flames destroying several large hillside properties in the exclusive region.