A helicopter tries to put out the wildfire in California's Napa, the United States, on Oct. 10, 2017. (Photo/Xinhua)

The series of deadly wildfires in northern California have claimed 21 lives, Californian Governer's Office of Emergency Services (Cal OES) told a press conference in Sacramento in northern San Francisco Wednesday.

Earlier in the day, Sonoma County Sheriff Rob Giordano told another press conference in Santa Rosa, about 90 kilometers away from San Francisco, Western California that the death toll from north California wildfires may continue to rise and the the number of people reported missing has gone up to 560 in Sonoma county.

He said the county sheriff had originally received reports of 670 people unaccounted for in the wildfires in Sonoma county, but 110 of them were located safe and sound later, cutting the number of missing people to below 600.

Giordano confirmed 11 people have died in Sonoma County from the Tubbs Fire, which accounted for the majority of the 21 deaths in the statewide wildfires in California, the most devastating wildfires in the history of the state.

"The individuals who died were found as the result of police and sheriff's deputies being called to neighborhoods for various reasons," he said, adding that teams put together to excavate the burned area for bodies have yet to begin their work.

"When we start doing searches, I expect that number to go up," Giordano said.

Santa Rosa, which is the largest city in California's Wine Country and the fifth most populous city in the San Francisco Bay Area, was among the counties hardest hit in the California wildfires.

Giodano said the county authorities have ordered madatory evacuations in many areas impacted by the wildfires, and the evacuation order may remain in place throughout this week.

California wildfires have burned nearly 170,000 acres of land as of Wednesday, and the blaze has been burning in Sonoma, Napa, Mendocino and Yuba counties since it broke out Sunday.

More than 3,500 homes and other structures have been leveled to the ground in one of the worst fire disasters in the California.

Tens of thousands of households are without power in Sonoma County. Pacific Gas and Electric Company is working to restore power to 50,260 customers impacted by the wildfires in the County.

About 28,000 customers have no access to gas service in Santa Rosa, Windsor, Yountville, Napa, and Kenwood, said Shirlee Zane, chair of the Sonoma County Board of Supervisors.

The deadly fires in North Bay of California have caused serious damage to the state, and thousands of people were forced to be evacuated, with a large number of homes and commercial facilities, including hospitals and even parks, completely destroyed.