Oscar-winning film-maker Quentin Tarantino has joined hundreds of demonstrators waving signs, shouting through megaphones and marching along New York City's streets to protest against police brutality.

The protest came at a time of heightened awareness across America of the often-contentious relationship between police officers and the people they serve. New York's mayor and police commissioner have said they are serious about enacting smart reforms to build trust between police and communities.

"I'm a human being with a conscience," said Pulp Fiction and Reservoir Dogs director Mr Tarantino, 52, who flew in from California for the event.

"And if you believe there's murder going on then you need to rise up and stand up against it. I'm here to say I'm on the side of the murdered."

The group gathered in Manhattan's Greenwich Village neighbourhood at Washington Square Park before marching about two miles along Sixth Avenue. The protesters walked past lines of police officers who had cordoned off a lane of traffic for them.

As they moved, those with megaphones shouted stories as others waved signs with photos of the dead, mostly young black men, and the dates and places of the incidents.

The event was the last of three demonstrations by the group RiseUpOctober in New York this week. Speakers at the protest said they want to bring justice for people killed by police.

Temako Williams, whose son, La-Reko Williams, was killed by police in 2011 in Charlotte, North Carolina, walked arm-in-arm with academic and activist Cornel West, one of the organisers. A federal jury ruled that a Charlotte-Mecklenburg police officer, who did not face criminal charges, had used excessive force, and it awarded her 500,000 dollars.

But, she said, the money was no substitute for justice.

"It wasn't worth the price of my son's life," she said. "It's a wound that won't heal."

While police were present all along the protest route, the day was peaceful. No arrests were reported.

But the protest was also days after a New York police officer, Randolph Holder, was shot dead while chasing a bicycle thief. A suspect has been charged with murder and robbery.

The Rev Al Sharpton dedicated his weekly radio broadcast and rally at his National Action Network headquarters to Mr Holder. He and others went to the Brooklyn neighbourhood where the policeman served to lay a wreath and pray for him and his family.

Activist Carl Dix, who helped found RiseUpOctober with Mr West, said that while he sympathised with Mr Holder's family, the officer's death did not affect the need to hold Saturday's rally as scheduled.

"That's not what this is about," he said. "This is about all the people who are murdered by the police."