Washington, Jul 20 (IANS): A wildfire is raged across 45,000 acres outside the Yosemite National Park, causing the evacuation of 4,000 residents.

The blaze that started on Sunday near Lake McClure and was only 7 per cent contained by Wednesday afternoon, according to the California Department of Forestry and Fire Protection (CAL FIRE).

More than 2,200 firefighters together with a crew from the Southern California city of Lompoc were fighting the blaze, reports Xinhua news agency.

About 4,000 people have been evacuated under a state of emergency issued by California Governor Jerry Brown on Tuesday, including the entire city of Mariposa, a few miles west of the park, 440 km north to Los Angeles.

Video clips posted by FOX 13 showed that downtown Mariposa of 2,000 residents with century-old wooden buildings, was empty except for firefighters and other emergency workers. Fierce flames were visible on slopes about a mile away.

"You couldn't even see the sun in the ash-filled sky," Tony Munoz, a school custodian who was among those evacuated from Mariposa, told FOX 13.

Yosemite National Park is still open, spokesman Scott Gediman said on Wednesday, but the fire closed one of several roads into the park.

Moreover, due to the heavy smoke blowing in from "Detwiler Fire", an air quality alert was issued on Wednesday for the Reno-Sparks area in Nevada state, more than 241 km away.

The wildfire is one of 17 large wildfires burning in California.