Los Angeles police officers and protesters denouncing the George Zimmerman verdict were playing a cat-and-mouse game Monday night as chaos continued along Crenshaw Boulevard and police declared an unlawful assembly.
The unlawful assembly was declared shortly before 10 p.m.
Earlier, groups of young people were running along area streets as officers responded to hot spots and set up skirmish lines to try to contain the roaming bands. Groups of people stampeded through Leimert Park, where a peaceful rally took place Monday evening before groups of youths splintered off and began engaging in lawless actions.
At least one fire was set in a trash can, and another youth hurled a trash can at a window of a Jack in the Box restaurant.
Los Angeles Mayor Eric Garcetti used Twitter to urge people to maintain the peace.
"I commend Leimert Park prayer attendees for practicing peace," he said. "I call on people on Crenshaw to follow their example."
The LAPD declared a tactical alert about 9 p.m., which means that off-duty officers can be held on duty when their shifts end and may respond only to high-priority calls.
The LAPD arrested at least one person but vowed to take more into custody if the lawless actions continued.
"We want to support everyone's 1st Amendment right to protest, but we also want to ensure public safety and not allow people to commit violent acts," Cmdr. Andy Smith told The Times.
Police estimated that 80 to 150 people were engaged in lawless activity along Crenshaw as they jumped on top of vehicles and appeared to assault bystanders.
Some protesters ignited fireworks in the middle of Crenshaw.
Zimmerman, 29, was acquitted Saturday in Florida of second-degree murder and manslaughter in the 2012 shooting death of Trayvon Martin, 17.
The verdict has sparked protests across the county and led to arrests over the weekend in Oakland and Los Angeles.