A California beach town descended into chaos over America's Independence Day weekend after a so-called "TikTok takeover" sparked violent disorder that ended with more than 400 arrests.
The unrest unfolded on Saturday evening on the Balboa Peninsula in Newport Beach after social media posts encouraged thousands of young people to descend on the popular coastal destination.
Police said the crowds grew so quickly that officers from 17 neighbouring law enforcement agencies were called in to support around 350 Newport Beach officers already on duty.
By around 8.30pm, authorities declared an unlawful assembly and urged residents to stay indoors as violence escalated.
Explosive mortars and fireworks were launched at police officers, into crowds and towards families with children.
One officer was struck by a mortar and required treatment at the scene.
A nearby supermarket was looted while fights broke out across the peninsula, shopfronts were damaged and roads became gridlocked, restricting access for emergency vehicles.
Witnesses reported traffic signs being ripped from the ground, palm trees being damaged and objects being thrown at police vehicles.
Police said the crowds grew so quickly that officers from 17 neighbouring law enforcement agencies were called in for support
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The powerful fireworks also damaged vehicles and triggered car alarms throughout the area.
By the end of the operation, police had arrested 402 people.
Newport Beach Mayor Lauren Kleiman condemned those responsible in a post on social media.
"To anyone who threw mortars at our officers and into crowds, started fights, destroyed property, or ignored police commands, enjoy your view from your jail cell," she wrote.
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The powerful fireworks damaged vehicles and triggered car alarms throughout the area
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She also criticised parents who allowed their children to attend unsupervised.
"To all the parents who sent their kids here without chaperones, good sense, or respect for law enforcement, shame on you," she said.
The mayor described the violence as "an attack on our community" and vowed to prevent similar incidents in future.
The Newport Beach Police Association blamed social media for fuelling the unrest.
By the end of the operation, police had arrested 402 people
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"A large group of agitators invaded Newport Beach, spurred on by an alleged 'TikTok Takeover.' These persons came to our city with the intent on causing harm, injury and destruction," it said.
Long-time residents said they had never witnessed disorder on such a scale.
John, who has lived in the area for more than 50 years, told KTLA: "This year was the worst I've ever seen. Last year was kind of a little crazy, but this year was a riot."
Another witness, Robert Burgeson, described seeing "probably 1,000 teens and young adults" flood the area, leaving him unable to leave a supermarket car park.
Other residents said they were shocked by the level of violence, describing it as unlike anything they had previously experienced in Newport Beach.