Image copyright MARK RALSTON Image caption The Thomas fire has destroyed about 900 properties, including 690 homes

A California firefighter has been killed by a wildfire burning across Ventura and Santa Barbara counties.

Fire chief Ken Pimlott said the victim was apparatus engineer Cory Iverson, 32, a father-of-one whose wife is pregnant with a second child.

Iverson was part of a crew battling the Thomas Fire, one of six major blazes currently raging in the state.

The Thomas fire has grown to 379 square miles (981 sq km), becoming the fourth-largest in California's history.

It has destroyed more than 900 properties, including 729 homes, two residential apartment blocks, two hotels and 18 other commercial properties, and scorched an area the size of New York and Paris combined.

The California Department of Forestry and Fire Protection (Cal Fire) did not give out any more details about Iverson's death, but it followed reports earlier in the day of a fire unit being overrun by the blaze near the town of Fillmore.

Media playback is unsupported on your device Media caption The long battle against California wildfires

Cal Fire said on Thursday that the Thomas blaze was 30% contained, up from 20% on Tuesday, but it continues to grow.

The agency said 8,144 firefighters were tackling the blaze, using 1,004 fire engines, 59 water tenders and 80 bulldozers. More than 30 helicopters and six air tankers are reportedly involved in the fight.

Several thousand of those firefighters are prisoners. According to local news station KPBS, they are paid $2 per day and and additional $1 per hour when they are actively fighting fires.

Steep slopes and rocky terrain have made it dangerous to tackle the flames.

Efforts to combat the Thomas wildfire have already totalled more than $48 million (£36 million). Many local school districts have cancelled classes and will not reopen until after the new year.

The blaze - named according to where it started, near the Thomas Aquinas College - is by far the largest of six major fires alight in the state.

The Thomas fire shows no signs of letting up as gusts of wind up to 40mph (65km/h) and low humidity pose a continued challenge to firefighters.

'Fire is coming right at you'

By James Cook, Los Angeles Correspondent

Radio traffic between firefighters and their controllers on Thursday morning gave a glimpse of the terrifying reality of tackling this monster blaze.

"Fire is coming right at you," said one message as units in the Fillmore area on the far eastern edge of the wildfire were ordered to pull back.

The weather had apparently changed suddenly, posing a threat to the lives of the firefighters in the area.

There were reports of a Mayday call, a rescue helicopter was scrambled and controllers attempted to contact a firefighter who was said to be "down" in the area.

The confirmation that a fire engineer had died came quickly. The man's family have been told of his death.