Soon after Wednesday's grand jury decision over Eric Garner's chokehold death, hundreds of protesters converged on Rockefeller Center and in New York City's iconic Times Square chanting "No justice, no peace."

They were reprising the rallying cry of demonstrators already angered by a separate verdict last week not to indict a white policeman in the fatal shooting of black teenager Michael Brown in Ferguson, Missouri.

Police said Thursday that 83 people were arrested overnight, mostly for disorderly conduct.

Police were deployed in force but no major incident of violence was reported.

A series of small protests converged into a large march down Broadway and eventually into Times Square.

The July death of Garner is one of a string of high-profile, racially charged incidents in which white police officers have been accused of using unreasonable force or being too quick to fire at black suspects.

The Garner and Brown cases, coupled with the death of a 12-year-old black boy who was gunned down by police officers in Ohio while handling a toy pistol in a playground, have reignited a longstanding debate in the United States about relations between law enforcement and African Americans, as well as accusations of overly aggressive policing.

Attorney General Eric Holder said the US Justice Department will launch a federal civil rights investigation into the case of 43-year-old Garner, who died after New York police officer Daniel Pantaleo placed him in a chokehold during an arrest for selling untaxed cigarettes on the New York borough of Staten Island.

An amateur video of the arrest shows Garner, a heavy-set man who suffered from asthma and had six children, gasping "I can't breathe, I can't breathe" as police officers held him to the ground with his throat constricted.

Holder's announcement means Pantaleo could still face trial.

Protesters in Times Square waved signs reading "Black lives matter" and "Respect human lives."

There was another protest on Staten Island and at Grand Central Terminal, where about 50 protesters lay, pretending to be dead.

Small demonstrations also broke out in Harlem, Union Square and Columbus Circle, while there were similarly small but peaceful protests in Washington.

"The police has impunity. They can run away whatever they do," New York demonstrator Susan Schneider told AFP.

"And when you see them on the streets, how they are equipped, it's like war. It's worse than in the 60s. The racism is stronger now."

'An American problem'

Garner's widow, Esaw Garner, said she rejected Pantaleo's apology. "Hell, no," Garner said, in comments reported by The New York Times. "The time for remorse for the death of my husband was when he was yelling to breathe.

"My husband is six feet under and I'm looking for a way to feed my kids now."

In brief comments following the grand jury decision, Barack Obama -- America's first black president -- addressed the inherent mistrust many African Americans have of police.
"We're seeing too many instances where people do not have confidence that folks are being treated fairly," Obama said.

"In some cases, those may be misperceptions, but in some cases that's a reality, and it is incumbent upon all of us as Americans... that we recognize this is an American problem and not just a black problem or a brown problem."

The August shooting death of 18-year-old Brown by a white policeman in Ferguson sparked consecutive nights of violence and became a rallying cry for African-American communities across the United States fed up with what they say is racially biased policing.

A grand jury in that case also decided not to charge the white officer involved, triggering demonstrations in cities across America last week and into the weekend.