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The Rev. Al Sharpton(C) is surrounded by police before being arrested at a demonstration near New York City police headquarters and the Brooklyn Bridge in New York.

More than 50 people were arrested in New York Wednesday, police said, after city-wide protests against last month's acquittal of three policemen who killed a unarmed black man on his stag night.

"Over 50 were arrested," a police spokeswoman said, adding that US civil rights activist Al Sharpton was among those held. She said there were "no reports of violence or wounded."

Several hundred people gathered in front of the police headquarters in southern Manhattan waving banners saying: "No justice, no peace," and "This whole damn system is guilty."

Other protests took place in Harlem, near Central Park and in Brooklyn, and demonstrators blocked traffic on the Queensboro, Triborough and Brooklyn bridges, organizers said.

On November 25, 2006, three policemen in plain clothes fired more than 50 bullets at a 23-year-old black man, Sean Bell, as he left a club where he had been celebrating on the eve of his wedding.

Bell died on the spot and two of his friends were wounded. An investigation showed that none of the victims was armed.

Two of the detectives, Gescard Isnora and Michael Oliver, were charged with manslaughter and faced a possible 25 years in jail. The third, Marc Cooper, faced a year in jail on the lesser charge of reckless endangerment.

Last month, a court in the borough of Queens, where the shooting took place, acquitted all three men.

The police officers had been staking out the nightclub where Bell had gone for his stag night. They said they fired their guns after Bell's car nearly ran them over, and always maintained that he and his friends were armed.

Bell's cousin, Robert Porter, 44, told AFP that the protesters would keep up their demonstrations "every day, with the sun shining or under the rain."

"We want justice, it is as simple as that. I don't care to be arrested, because we are fighting for a reason," he said.