LOS ANGELES, United States -- Three people suspected of being part of a robbery flash mob were being questioned Tuesday, the latest in a series of violent thefts in California involving sometimes dozens of people.

At least 20 raiders in four cars took part in a smash-and-grab at a Los Angeles department store Monday evening, taking a sledgehammer to the display window and loading up on men's clothing.

As police arrived the group split up, with one vehicle leading officers on a high-speed chase along the city's freeways, which ended with a foot pursuit and the arrest of the three.

The robbery followed two similar attempts to smash through the windows of the Louis Vuitton and Saks Fifth Avenue stores in swanky Beverly Hills on Sunday.

Police said those raids were unsuccessful.

On Saturday, an 80-strong gang swarmed a department store in Walnut Creek near San Francisco, scooping up armsful of clothes and bags.

Police there said it was "clearly a planned event", according to the San Francisco Chronicle.

Gangs of thieves wielding hammers targeted several other stores in the Bay Area over the weekend, including in San Francisco's Union Square.

Videos on social media show masked raiders racing out of a Louis Vuitton store carrying bundles of apparently stolen merchandise, with police officers arresting one man as others ran away.

In nearby Oakland, gangs targeting cannabis retailers opened fire on police when they were confronted.

"We do have intelligence that it’s a collective group of people, multiple groups coming together to commit these attempted burglaries," Oakland Police Chief LeRonne Armstrong said, according to the Chronicle, adding that the heists appeared to be organized through social media.

Despite the high-profile spree, figures from California's Department of Justice show crime in the state is at historically low levels.

However, reports suggest robberies have ticked up in 2021 compared to a year earlier, when pandemic restrictions are credited with reducing many categories of crime.