SAN FRANCISCO - Wildfires in northern regions of the US state of California were threatening thousands of homes Sunday night, forcing thousands to evacuate.

According to the California Department of Forestry and Fire Protection, more than 12,000 acres (around 48.6 hectares) of forest have been destroyed by the so-called "Ponderosa Fire" after lighting strikes on Friday night and Saturday morning set off a dozen fires in northern California.

About 1,000 firefighters have been dispatched to protect homes and commercial buildings, but the blaze has yet to be contained, a spokesman for the agency told the San Francisco Chronicle newspaper.

A mandatory evacuation was issued Sunday evening for the communities of Canyondam in Plumas County, a town 154 miles (about 247.8 km) north of Sacramento, California's capital.

Nearly 2,000 homes in several cities in the area were also ordered to evacuate Saturday night. The California Department of Forestry and Fire Protection estimated that more than 3,000 people have been displaced by the evacuation.

A Red Cross shelter has been established in Redding, county seat of Shasta County in northern California.