By Steve Gorman and Dana Feldman
LOS ANGELES (Reuters) - Hundreds of protesters staged boisterous but peaceful protests in Los Angeles and San Francisco late on Tuesday against the acquittal of a neighborhood watch volunteer charged with murdering unarmed black teenager Trayvon Martin.
Police and civic leaders appealed for calm but braced for more unrest after nearly two dozen people were arrested in Los Angeles and the San Francisco Bay area late on Monday in a second night of protests over a case that has captivated and polarized the U.S. public on race, gun and self-defense laws.
Protesters said they were angry at what they saw as a miscarriage of justice in the verdict reached on Saturday by Florida jurors who found George Zimmerman, the white-Hispanic man who shot Martin, not guilty of murder or manslaughter.
Public comments from one of the six jurors stoked anger further as they were widely regarded as too sympathetic toward Zimmerman, who said he acted in self-defense. He was accused of having singled out Martin as suspicious because he was black.
CNN said on Tuesday four other jurors released a statement distancing themselves from the juror's comments.
About 100 demonstrators, many of them holding placards bearing Martin's likeness, gathered in front of City Hall in downtown Los Angeles early in the evening chanting, "Your son, our son. We are all Trayvon" and "No justice, no peace."
"This is not just a protest. It's a movement for justice all across the country," organizer Eugene Puryear, 27, from Washington, D.C., shouted to the crowd. "We won't get off the streets until there's justice for Trayvon Martin."
Puryear told reporters the aim of the rallies in various cities was to tap into anger over the verdict and "to channel that into a mass movement to attack the root of the problem."
"Trayvon Martin can be a symbol for a movement that says, 'No more' to racist violence, 'no more' to oppression and exploitation," he said.
About eight miles away in the predominantly black Crenshaw District, scores of people assembled on Tuesday evening in a public park as a steady stream of passing motorists honked their horns in support. Police helicopters were overhead.
The scene was loud but peaceful, with police staying mostly on the sidelines while making their presence known.
"This is supposed to be a peaceful demonstration, and we should respect the wishes of Trayvon's mother and father because they said that they don't want any violence," said Lawrence Warren, who was at the park with members of his family in tow.
On Monday night, a crowd estimated by police to have numbered 150 went on a rampage blocks away from the park, setting trash on fire, smashing windows and assaulting a television news crew. Fourteen people were arrested, most of them accused of disobeying orders to disperse.
Mayor Eric Garcetti later called for members of the public to exercise restraint and to avoid letting "passions" sparked by the case "ignite this city." Los Angeles Police Chief Charlie Beck said officers would take a "much stricter posture".
Police Commander Andrew Smith said minor infractions tolerated by police on Sunday and Monday, such as blocking traffic, would not be overlooked on Tuesday.
The LAPD's show of force would be "significantly above" the 300 to 350 officers present on Monday, he said. "The message is very clear: We expect everyone to act in a lawful manner."
Well after night fell, demonstrators in Los Angeles appeared to be heeding those warnings, though at one point, fireworks were set off about a block away from the park.
In San Francisco, about 150 people gathered at a rally that went off without incident on the steps of San Francisco City Hall on Tuesday evening.
About a third of the protesters wore hooded sweatshirts, or "hoodies," similar to the one Martin wore on the night of his death, and a single red sign popped up from the center of the crowd that read "Stand up for Justice." Some attendees held candles decorated with images of Martin's face.
Lynn Banks, 55, an account manager who attended the protest with her son, said Zimmerman's acquittal left her heartbroken.
"My first thought was there is no hope for my son coming up in this world," she said. "We pass a Zimmerman every day - a wannabe cop that has an issue with young black men."
In Oakland, across the bay from San Francisco, police arrested one person at a small protest, police spokesman Randy Wingate said.
About 250 protesters swarmed downtown streets of the city on Monday night, vandalizing cars and businesses and scrawling graffiti. Nine people were arrested.
No serious injuries were reported in either Oakland or Los Angeles on Monday, but officials urged organizers to keep further protests peaceful.
A statement signed by Oakland Mayor Jean Quan and other city officials called the death of Martin "a tragic event felt throughout the community," adding the city was committed to "supporting peaceful assembly and freedom of speech" following the "emotional" verdict.
Some Oakland residents on Tuesday criticized the city's police department for what they saw as a failure to prepare for demonstrations following the verdict.
"It didn't seem as if Oakland watched the trial," Evelyn Hogan-Jackson told the City Council. "I'm really tired of paying for your mistakes, of paying for your lack of planning."
Assistant Chief Paul Figueroa said Zimmerman's acquittal caught his department off guard on Saturday night and the police insufficiently staffed the protests on Sunday and Monday nights.
He said the city had its largest contingent of officers out on Tuesday night, and the interim police chief planned to meet with business leaders on Wednesday to discuss the situation.
"This violence is unacceptable," he said.
(Reporting and writing by Steve Gorman; additional reporting by Ronnie Cohen and Laila Kearney in San Francisco; Editing by Cynthia Johnston, David Brunnstrom, Tim Gaynor and Elizabeth Piper)