(CNN) -- An aggressive wildfire has burned 10 homes and spread across 3,000 acres in Northern California, officials said Thursday.

A wildfire in the Santa Cruz Mountains is causing mandatory evacuations for neighboring homes.

Flames were threatening at least 50 more homes, the California Department of Forestry and Fire Protection said.

About 200 children at a 4-H Club camp were told to take immediate shelter as high winds fanned the flames in the Santa Cruz mountains.

The wildfire was burning in rugged terrain in Santa Clara County and moving south towards Santa Cruz County, south of San Francisco.

About 190 people from the two counties had been evacuated, officials said.

The Summit Fire began around 5:30 a.m. PT (8:30 a.m. ET) Thursday near Mount Madonna County Park in Santa Clara County.

Five fixed-wing aircraft and four helicopters were dropping water on the fire, fanned by sustained winds of 15 mph to 20 mph with gusts up to 40 mph.

Officials ordered a so-called Supertanker, a jumbo jet modified to battle fires from the air.

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State fire officials said at least 149 firefighters but likely many more were battling the blaze, which is being fueled by dry brush. Strike teams from across Northern California were being mobilized.

Aerial video footage from local TV station helicopters showed structures and vehicles engulfed.

The Santa Cruz Mountains are dotted with multimillion-dollar homes.

The Santa Clara and Santa Cruz sheriffs were handling evacuations.

A Red Cross evacuation center was established at the Santa Cruz County Fairgrounds, said Officer Dinah Phillips, a spokeswoman for the Santa Cruz County Sheriff's Office.

CNN's Augie Martin contributed to this report.