Protesters chanted "I can't breathe" after a grand jury declined to indict a white police officer in the death of Eric Garner — a case that was recorded on video and showed the unarmed black man repeatedly gasping as he used the phrase.
Demonstrators staged a "die-in" in the main concourse of Grand Central Terminal and took over a section of Manhattan's West Side Highway and crowds also gathered at Times Square, Union Square and Foley Square, according to NBC New York.
Police said Thursday they made 83 arrests at various protests around New York City on Wednesday night.
"I'm outraged," John Grauwiler, 44, said as he joined protests in Times Square. "As a man of color, I'm concerned about the implications of this for me and my friends. This is a wake-up call."
A grand jury on Wednesday declined to indict NYPD Officer Daniel Pantaleo in the death of Garner, 43, who died after being placed in a chokehold while being arrested for allegedly selling untaxed cigarettes on Staten Island on July 17.
The medical examiner ruled Garner's death a homicide and found that a chokehold contributed to it.
"I can't breathe" became a rallying cry as crowds gathered in Times Square. Protesters also held their hands up — referencing the death in Ferguson, Missouri, of Michael Brown, who was killed by a police officer who was also not indicted — and held signs reading "Black Lives Matter."
Mayor Bill de Blasio called for peaceful protests and vowed police reforms, including training officers on alternative ways to resolve conflicts. He talked about Garner's death and the mistrust between some minority communities and the police in highly personal terms, as his son Dante is biracial.
"[Wife] Chirlane and I have had to talk to Dante for years about the dangers he may face … we've had to literally train him, as families have all over this city for decades, in how to take special care in any encounters he has with police officers, who are there to protect him," de Blasio said, adding that it would be an emphasis of his administration to bridge gaps in understanding between police and the community.
U.S. Attorney General Eric Holder announced Wednesday that the Justice Department will launch a civil rights investigation into Garner's death.
In the Staten Island neighborhood where Garner died, people reacted with angry disbelief and chanted, "I can't breathe!" and "Hands up — don't choke!"
"This fight ain't over, it just begun," Garner's widow Esaw said.
Protesters like Doug Brinson said the decision not to indict was an insult.
"Not to indict the man is like a double slap in your face," Brinson told NBC New York. "It's like stomping you down on the ground."
"I grew up in the '60s and '70s, we fought to have justice and 40 years later we still don't have justice in this country," said protester Walter Cooper, 65. "I'm very frustrated and upset."
"A murderer was caught on camera, and for whatever reason they [the grand jury] decided to let a murderer go free, and this keeps happening," said protester Adina Bloom, 25, as she marched with others to the Rockefeller Center Christmas Tree lighting from Times Square. "I don't understand how much more evidence one has to present to face consequences. What more could we have done to show the people of the court a murder occurred?"
NBC News' Phil Helsel and The Associated Press contributed to this report.