NEW YORK (AP) -- Grandparents brought their grandchildren. Experienced activists marched alongside newcomers. And black and brown protesters chanted slogans with whites.

Demonstrators protest against the decision of a grand jury not to indict the police officer involved in the death of Eric Garner carry several fake coffins carrying the names of killed in clashes with police while crossing the Brooklyn Bridge (AP Photo / Jason DeCrow)

In New York City and around the country thousands and thousands of diverse people united by anger over a grand jury clearing a white police officer in the chokehold death of an unarmed black man took to the streets for a second night.

"We're under siege and it has to stop," Harlem resident Judy Edwards said at a rally Thursday night in lower Manhattan's Foley Square, surrounded by courthouses and other official buildings.

The 61-year-old black woman was accompanied by her daughter and twin 10-year-old grandchildren, a boy and a girl. She said it was important to her that the children saw a crowd that was racially mixed and diverse in many other ways all insisting upon the same thing - that something must be done.

That was the message, too, in cities across America: Atlanta, Boston, Chicago, Denver, Detroit, Minneapolis and Washington, D.C., among them. Sign-carrying, chanting demonstrators marched down heavily-traveled streets and shut down highways and bridges. Politicians talked about the need for better police training, body cameras and changes in the grand jury process to restore faith in the legal system.

In New York, Mayor Bill de Blasio - blasted by police union leaders who accused him of not supporting his officers - outlined previously announced plans to teach officers how to communicate better with people on the street.

Protestors occupy Herald Square during march in New York, against a grand jury's decision not to indict the police officer involved in the death of Eric Garner (AP Photo/John Minchillo)

President Barack Obama also weighed in, saying one of the chief issues at stake is "making sure that people have confidence that police and law enforcement and prosecutors are serving everybody equally."

But U.S. Rep. Peter King, R-N.Y., told The Associated Press: "The black community is not right to be upset about the ruling. If this were a white person it would have been the same thing."

Tensions already were high after a grand jury last week cleared an officer in the shooting death of 18-year-old Michael Brown in Ferguson, Missouri. Then on Wednesday came the decision that Officer Daniel Pantaleo would not be indicted in the chokehold death of Eric Garner. In both cases the officers were white and the victims were black.

New York demonstrators targeted the city's major traffic arteries again on Thursday. They gathered near the Holland Tunnel, the Manhattan Bridge and on the Westside Highway, temporarily shutting them down. One group converged on the Staten Island Ferry Terminal. Authorities said arrests were made.

New Orleans residents held a die-in at a holiday light show and police moved in to separate them from spectators, some of whom yelled at the demonstrators.

In Chicago, hundreds of protesters blocked Lake Shore Drive. The protesters were thwarted in their efforts to march to Soldier Field, where the Chicago Bears and the Dallas Cowboys were playing.

In Washington, protesters gathered in front of the Justice Department and marched close to the Ellipse where holiday revelers - including the president and his family - celebrated the lighting of the national Christmas tree. A second march went from the district's police headquarters to city hall, where former D.C. Mayor Marion Barry's remains are lying in repose.

At a news conference in New York on Thursday after a night of protests led to 83 arrests, the Rev. Al Sharpton called the state-level grand jury system "broken" when it comes to police brutality cases and urged federal authorities to fix it.

"The federal government must do in the 21st century what it did in the mid-20th century," he said. "Federal intervention must come now and protect people from state grand juries."

But Stuart London, Pantaleo's attorney, expressed confidence Thursday that his client won't face federal prosecution. "There's very specific guidelines that are not met in this case," London said. "This is a regular street encounter. It doesn't fall into the parameters."

Associated Press writers Tom Hays, Colleen Long, Karen Matthews and Jonathan Lemire in New York and Eric Tucker in Washington contributed to this report.

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