Image copyright AFP Image caption Residents of Lake Elsinore are fleeing the advancing flames

More than 21,000 people have been evacuated from the path of a fast-moving wildfire in Southern California.

The mandatory evacuation orders were issued as the blaze, dubbed the Holy fire, threatened homes around Lake Elsinore in Riverside County.

The fire, one of several across the state, has destroyed more than 19,000 acres of forest north of San Diego.

Meanwhile, a man suspected of starting the Holy fire has appeared in court accused of arson.

Forrest Clark made several outbursts during the hearing in Orange County, at times refusing to show his face, local media reported.

His case was adjourned until 17 August and bail set at $1m (£783,000), at which point Mr Clark interjected: "I can handle a million (dollars) right now, easily."

Mr Clark was arrested on Tuesday outside his cabin after a brief standoff with officers.

Authorities say he intentionally started the fire on Monday after a decade-long dispute with neighbours.

According to Orange County officials, Mr Clark had emailed the local volunteer fire chief to threaten "this place will burn".

Image copyright ORANGE COUNTY SHERIFF'S DEPT Image caption Forrest Clark, 51, is accused of starting the fire after a long dispute with neighbours

The BBC's Peter Bowes in Los Angeles says high temperatures, gusty winds and tinder dry brush have fuelled the disaster in Orange County.

Steep, inaccessible terrain has hampered crews tackling the Holy fire and the blaze was only 10% contained on Friday.

Experts warn that worsening weather conditions, with thunderstorms in the forecast, could lead to "extreme fire behaviour" over the next few days, he adds.

The US National Weather Service says smoke from weeks of California wildfires, and others burning in the western US, has drifted over a vast area, affecting air quality "across the northern Rockies into western and central Canada and south over the northern Plains".

Image copyright Getty Images Image caption Firefighting aircraft are dropping fire retardant around Lake Elsinore

More than 600 firefighters are battling the Holy fire, which is one of at least 18 wildfires raging across California.

The Mendocino Complex fire has been declared the largest in state history and has already engulfed 290,692 acres.

Fire chiefs say they expect it to burn for the rest of the month.

Another blaze - the Carr fire, further north - has killed at least seven people and destroyed more than 1,500 structures. On Friday it was declared 51% under control.

Across the state, at least 14,000 firefighters are struggling to contain the multiple outbreaks.

The crews have been boosted by US army personnel and more than 1,000 prisoners. The inmates - who are considered low-risk offenders - work on a volunteer basis but also receive $2 (£1.50) a day, plus $1 an hour.

Fire crews from Australia and New Zealand have also flown over to share their expertise in battling bush fires.