Protests in California over George Zimmerman's acquittal went from violent one night to brief, small and subdued the next after authorities beefed up patrols and vowed to crack down on further disturbances with quick action and arrests.

On Tuesday night, a group of about 200 people _ at times appearing outnumbered by police _ marched through downtown Los Angeles between City Hall and police headquarters, briefly blocking traffic but remaining peaceful. They were flanked by officers on bicycles and on foot but did not challenge or provoke them.

Another rally at a park near the city's Crenshaw District was nearly as calm.

The same area was a different picture a night earlier, when 14 people were arrested after about 150 split from a peaceful demonstration and ran through the streets, jumped on cars, tried to break store windows and punched bystanders. A Wal-Mart store was vandalized.

Police Chief Charlie Beck and new Mayor Eric Garcetti said after Monday's problems that peaceful protests were welcome but violence wasn't _ vowing an increased police presence and no tolerance for mayhem.

"Rights will be respected," Garcetti said on his Twitter account. "Crime will not be tolerated."

Los Angeles and Oakland had been flashpoints for violent reactions to Saturday's acquittal of Zimmerman in the death of Trayvon Martin in Florida.

A few dozen demonstrators watched closely by police in riot gear gathered at Oakland City Hall. A night earlier, protesters left a City Hall gathering and blocked a freeway, threw fireworks and assaulted a restaurant waiter with a hammer. Nine people were arrested.

In San Francisco, a peaceful crowd that gathered Tuesday evening at City Hall listened to speeches by NAACP leaders and sang "We Shall Overcome."

Los Angeles officials are sensitive to images of unrest in a city where the 1965 Watts Riots resulted in 34 deaths, and 1992 violence following the acquittal of four white officers in the beating of black motorist Rodney King left 55 people dead and thousands injured.

The LAPD has spent years building relationships in the black community, and is working with African-American leaders to head off more serious violence. More than 300 police officers responded to the Crenshaw demonstration. They were intentionally slow to directly engage protesters, to allow a peaceful end to the demonstration.

Los Angeles Police Commissioner John Mack, a former president of the Los Angeles Urban League, said the public needs to differentiate between the troublemakers and the peaceful demonstrators.

"It's important we don't get carried away and get so focused on the few, who in my opinion clearly were not a part of the organized group and had their own agenda," Mack said. "Quite frankly, I'm not so sure that all of them even cared about Trayvon Martin."

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Associated Press writer Terry Collins in San Francisco contributed to this report. Tami Abdollah can be reached at http://www.twitter.com/latams