Firefighters in the United States are battling a wildfire in Malibu, California that is near Pepperdine University and prompting evacuations of about 6,000 people and more than 2,000 structures, according to local media.

Students sheltering at the Pepperdine library early on Tuesday watched as the sky turned deep red.

“Just seeing the flames grow and seeing that bright red colour of fire just get brighter and brighter and brighter — it was so scary,” student Gabrielle Salgado told KABC-TV. The university later said the worst of the fire had pushed past the campus.

It was not immediately known how the blaze, named the Franklin Fire, started. But Los Angeles County Fire Department officials estimated that more than 7.2 square kilometres (2.8 square miles) had burned and structures were threatened.

A damage estimate was not available, but “it’s certain some number of homes are definitely going to be badly damaged”, Matt Myerhoff, a spokesperson for the city of Malibu, told KABC-TV.

The blaze caught alight amid dangerous seasonal fire conditions because of Southern California’s notorious Santa Ana winds.

Thousands of people were ordered to evacuate last month after a wildfire northwest of Los Angeles blew flames into ranches and neighbourhoods, destroying dozens of homes.

On Tuesday, Pepperdine cancelled classes and finals for the day and there was a shelter-in-place order. Fire engines were on campus and helicopters were dropping water collected from lakes in the school’s Alumni Park onto the fire.

“The university understands the worst of the fire has pushed past Pepperdine. However, there are smaller spot fires on campus that are not threatening life or structures, and fire resources remain on campus to address these spot fires as they occur,” Pepperdine posted in a statement online.

Power to tens of thousands of people had been shut off by Monday night as utilities worked to mitigate the impacts of Santa Ana winds, whose strong gusts can damage electrical equipment and spark wildfires.

Santa Anas are dry, warm and gusty northeast winds that blow from the interior of Southern California toward the coast and offshore. They typically occur during the autumn months and continue through winter and into early spring.

The National Weather Service issued a red flag warning for high fire risk with a rare “particularly dangerous situation,” or PDS, designation starting at 8pm Monday into Tuesday for Los Angeles and Ventura counties.

The LA County Fire Department issued a mandatory evacuation order for residents living east of Malibu Canyon Road and south of Piuma Road.