Thousands of people in New York rallied in solidarity with residents of Ferguson on Thursday, showing support to people across the US who have been victims of police brutality. The NYPD threatened mass arrests if people did not stop blocking traffic.

The New York City Police Department has arrested at least four people during a peaceful rally intended to pay tribute to Michael Brown and others who have suffered from excessive police behavior.

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Thousands of protesters left their original rally location at New York’s Union Square and descended upon Times Square, ignoring police orders to stay on the sidewalk. As a result, police began cordoning protesters at 42nd Street and 9th Avenue. Demonstrators flooded social media, complaining that officers had kettled them and refused to let them go. No police in riot gear were at the scene, however, nor was any tear gas used as in Ferguson, Missouri, on Wednesday.

A number of arrests were made as the situation escalated, although the exact number remains unclear. Eventually, police told protesters they would be able to leave, but that if they returned to the current location and blocked the traffic again they would be arrested.

Hundreds of people at NYC Union Square for National Moment of Silence for Victims of Police Brutality. #NMOS14pic.twitter.com/ermqxxNTln — RT America (@RT_America) August 14, 2014

These developments come as thousands of people in more than 80 cities across the United States gathered on Thursday to hold vigils for victims of police brutality, particularly 18-year-old Michael Brown, who was fatally shot while unarmed by police in Ferguson.

Pulling together under the banner, “National Moment of Silence for Victims of Police Brutality” (NMOS), peaceful assemblies gathered at 7pm EST in about 37 states, including New York, California, Missouri, Michigan, and Texas. Twenty minutes later, groups observed a 60-second moment of silence, which was followed by participants sharing stories, marching, and chanting together.

The vigils were intended to honor the lives of innocent people killed by law enforcement, as well as those lives that have been touched by police brutality in any way. In addition to the recent death of Brown, New Yorker Eric Garner died from a chokehold by a police officer in July, and Ezell Ford of Los Angeles was fatally shot by law enforcement just two days after the incident in Ferguson.

“We will peacefully assemble at over 90 vigils across the nation to share in a moment of silence and solidarity with each other,” NMOS wrote on its Facebook page. “Today, we will show the world and each other that we can come together, as ONE.”

In New York City, vigils were held in Manhattan, Queens, and Brooklyn. Hundreds of people gathered at Union Square alone, where they chanted, “Hands up; don’t shoot!” together after observing their moment of silence. Similar chants were recorded in cities throughout the US.

“I’m sick of people of color being killed by police,” Harlem resident Sally Rumble told RT at Union Square. “It’s the same thing over and over again. America is not for black people.”

That sentiment was echoed throughout the rally, where demonstrators raised signs that read, “Black lives matter,” and “civil rights don’t expire at sundown.” Some protesters said they were scared about recent police behavior, and emphasized that no matter how futile protests may seem, it was important to express their beliefs.

David Roberts of the Bronx, meanwhile, said the NMOS vigil was the first rally he had ever attended, but wanted to participate after hearing about Brown’s death.

“I’m a young black man and that kind of thing could happen to me also,” he said, adding that he wanted to express his opposition to the militarization of law enforcement and was concerned with Americans losing their rights.