After two rival demonstrations converged near New York City Hall Friday afternoon—one supporting the New York Police Department and the other opposing police brutality—some anti-police protesters continued their march throughout Manhattan, temporarily taking over the Manhattan Bridge overpass and stalling traffic.

While the New York police brutality protesters focused on the police-involved killings of 18-year-old Michael Brown in Ferguson in August and 43-year-old Eric Garner in Staten Island in July, activists in Milwaukee, Wisconsin, gathered to remember another black man fatally shot by a police officer who hasn't had as much play in the national media.

See also: Making sense of the minority police officer experience

The Milwaukee demonstrators, like their counterparts in New York, took over a major thoroughfare, Interstate 43, during rush hour for Dontre Hamilton, 31, who was killed by a white police officer in April. Hamilton and the officer, Christopher Manney, got into an altercation at a park where Hamilton was sleeping. When Hamilton resisted a pat down, the two started fighting and hit each other with Manney's baton. Manney then shot Hamilton 14 times.

Manney was fired from his job because he didn't follow department procedures, but the Milwaukee County District Attorney has yet to decide whether to file charges.

Several Milwaukee freeway blockers were arrested, but protests continued later outside the Milwaukee Police Administration building in downtown, according to the Milwaukee-Wisconsin Journal Sentinel.

Pro-police demonstrators rally across from a group of anti-police demonstrators outside City Hall in response to a string of recent anti-police protests, Friday, Dec. 19, 2014, in New York. Image: ason DeCrow/Associated Press

Back in New York, authorities were warning of poor traffic conditions due to the protest. Recurring demonstrations have cropped up in New York and cities across the country for Brown and Garner in recent weeks.

#Protest activity: extensive #traffic delays on the upper & lower levels of Brooklyn bound MN Bridge. Consider alternate routes. — NYC OEM - Notify NYC (@NotifyNYC) December 20, 2014

#Protest activity: extensive #traffic delays on the upper & lower levels of Brooklyn bound MN Bridge. Consider alternate routes. — NYC OEM - Notify NYC (@NotifyNYC) December 20, 2014

After being pushed off the Manhattan Bridge by police, a crowd of anti-cop protesters returned to the City Hall demonstration, where police had separated the opposing protest groups with barricades.

The pro-police activists, who have a Facebook group called "Thank You NYPD" weren't endorsed by police unions, but said they were out to support a department that has been besmirched during recent rallies, according to CBS New York. Supporters of Brown and Garner have chanted "How do you spell racist? NYPD!" at marches as well as "Fuck the police."

The pro-police demonstrators held signs that said "Blue Lives Matter" and also used #BlueLivesMatter on social media, a play off the popular "Black Lives Matter" slogan that has been used at several marches for those killed by officers.

Some were also seen wearing sweatshirts that read "I Can Breathe," which protesters opposing the death of Garner, who was asthmatic and died while muttering "I can't breathe" after an NYPD officer held him in a chokehold, found offensive.

Protesters on both sides confronted each other verbally, but not physically, according to CBS.

grt pic RT @jjk607: NYPD widened the DMZ - far enough to limit physical contact but close enough to exchange anger pic.twitter.com/WHMzM6DY9B — Azi (@Azi) December 20, 2014

Meanwhile, in Wisconsin, Gov. Scott Walker said he was prepared to call in the National Guard if major protests unraveled there when a decision regarding Manney and charges is made, according to The Huffington Post.