LOS ANGELES, July 3 (Xinhua) -- More than 2,000 firefighters are battling the wild fire, dubbed "County Fire," in northern California, which has burned across an area of 70,000 acres (283.3 square km) by Tuesday morning.

According to the latest update by Cal Fire, California's agency responsible for fire protection, the fire which started over the weekend has affected multiple counties in three days.

About 2,162 firefighters are fighting the blaze on multiple fronts in both Yolo and Napa Counties with the help of 18 helicopters, 50 bulldozers and 187 fire engines, Cal Fire said, adding that more than 900 structures are still threatened by the fire.

Local Winters Express newspaper also reported Tuesday that a spokesman of Cal Fire confirmed California National Guard personnel have been at the fire command center from Monday to offer mutual assistance against the rapidly-growing wild fire.

The fire triggered evacuations throughout Yolo County, and hundreds of residents have been displaced.

Photos posted online show that thick smoke from the blaze were visible from as far away as Sacramento International Airport, about 90 km south of the scene.

So far, there is no report of structure destroyed or casualties.