By Jose Serrano (staff@latinospost.com) | First Posted: Apr 16, 2015 12:49 AM EDT

A day that started with peaceful anti-police violence protests ended with over 50 arrests nationwide and at least two injured New York Police Department officers.

Demonstrators took to the streets in dozens of cities Tuesday to denounce law enforcement's killing of unarmed black men. They blocked highways and surrounded police stations, referring to deaths of Michael Brown, Eric Garner, and Walter Scott as they ignored orders to disperse.

Most rallies included staged die-ins and social media posts with hashtags #BlackLivesMatter and #ShutDownA14; the latter referenced April 14, the day set by organizers like Justice League NYC and the Stop Mass Incarceration Network.

Over 100 San Francisco protesters halted a City Hall meeting. In nearby Oakland, the crowd around Oakland's police department washed onto Interstate 880 around 4 p.m. Mostly suburban Madison, Wisconsin - where unarmed black teen Tony Robinson Jr. was gunned down by police last month - saw hundreds of people black a major roadway into the city.

The Los Angeles Police Department said they arrested 15 individuals who, during rush hour, disrupted metro service along the Blue Line. Thirteen adults and two teenagers were put in cuffs around 5:45 p.m. after being given multiple warnings.

In New York, 42 people were arrested for various offenses ranging from resisting arrest to disorderly conduct to obstruction government administration. They marched on Broadway on their way to the Brooklyn Bridge where traffic came to a halt.

While protesters initially gathered in Union Square, all arrests either came on 1 Street Plaza in Manhattan or in downtown Brooklyn.

Two NYPD officer suffered non-life threatening injuries. An off-duty sergeant stopped in traffic out of his car only to be assaulted by unknown assailants. Another policeman patrolling the Crown Heights area was struck by a bottle.

"Violence or threats of violence against the police are unacceptable and will absolutely not be tolerated," said New York City Mayor Bill de Blasio in a statement issued Tuesday night. "These attacks will be thoroughly investigated, and we will urge the full prosecution of the perpetrators."

De Blasio added that violence towards anyone, police or citizen, is beneath the dignity of the city.

Just as protests were getting underway, dashcam footage of a Tucson, Arizona officer accelerating his police cruiser into a robbery suspect was released. The Feb. 19 video shows Officer Michael Rapiejko ramming his car into 36-year-old Mario Valencia, who flew into the air on impact.

Some question whether this was another instance of excessive force by law enforcement, despite the fact that Valencia was armed with a hunting rifle and had just completed a crime spree that involved stealing a car and starting a church fire.

Rapiejko has been cleared of any wrongdoing.

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