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By Phil Helsel, Elisha Fieldstadt, Matthew Grimson and The Associated Press

Hundreds of protesters were arrested across the country and 21 cops injured in Saint Paul, Minnesota, Saturday night as demonstrations continued nationwide over police violence.

Around 102 protesters were taken into custody in Saint Paul, while more than 100 people were arrested in Baton Rouge, Louisiana, police in both cities said.

Both cities continue reel after the recent deaths of two black men at the hands of police last week.

Related: Black Lives Matter Leader DeRay Mckesson Arrested

In St. Paul, protesters blocked Interstate 94 and chanted the name of Philando Castile, a 32-year-old man who was fatally shot by a St. Anthony police officer in Falcon Heights on Wednesday.

Protester block Interstate 94 in Saint Paul. Joe Danborn / AP

Minnesota Gov. Mark Dayton on Sunday urged for calm and thanked law enforcement officers for their "persistent attempts to resolve the situation peacefully."

"The occupation and shutting down of Interstate 94 last night were unlawful and extremely dangerous," Dayton said in a statement. "I urge everyone exercising their First Amendment rights to do so lawfully and without endangering themselves or others."

Police said on Twitter that people on an overpass were "throwing objects at officers, dumping liquid on officers" and others were throwing rocks and a construction material called rebar. Police also said a molotov cocktail was thrown at officers.

Police were heard telling the crowd, "leave the interstate now or you'll be subject to a use of force" shortly after 10:30 p.m. Police blamed "aggressors" for throwing objects at officers, and said police were using "marking rounds."

Twenty-one officers from multiple agencies were injured, the St. Paul Police Department said Sunday.

Authorities used smoke bombs when 200 protesters refused to leave the roadway just after midnight. By 12:45 a.m. Sunday, police said they were clearing debris from the road in order to reopen the highway.

Protesters respond to flashbangs rubber bullets & smoke grenades with #PurpleRain. The most MN ish ever.#i94closed pic.twitter.com/o4EAiTuMAv — Nick Espinosa (@CGoHome) July 10, 2016

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In Baton Rouge, Louisiana, hundreds of protesters gathered for another day of demonstrations over the fatal shooting of Alton Sterling. Some wore T-shirts that read, "I can't keep calm I have a black son" or "Black Lives Matter."

Louisiana Gov. John Bel Edwards said during a press conference on Sunday that he was heartened that protests were largely peaceful. He stressed that in order to maintain public safety, it was critical that demonstrations not spill over into major thoroughfares.

“The best way to honor the memory of Alton Sterling, the Dallas law enforcement officers and Philando Castile is for peaceful demonstrations here in Louisiana,” Edwards said.

Local authorities said 19 of the 101 demonstrators arrested on Saturday night were from out of state.

Prominent "Black Lives Matter" activist DeRay McKesson was among those detained. He live-streamed his arrest over Periscope and was later charged by police with "simple obstruction of highway commerce." McKesson was released from jail Sunday afternoon.

Now they're running after folks. https://t.co/wyWyJHcfc7 — deray mckesson (@deray) July 10, 2016

Baton Rouge resident Marie Flowers came to the protest with her three children.

Pointing to the crowds along a fence surrounding the police department she said: "To me, this is just a snapshot of north Baton Rouge and how frustrated they are. They are so frustrated with this bull crap."

At one point, she gestured to her 12-year-old son and said they were there to protect men like him. "Black boys are being killed and this is just the culmination of what has been going on for decades," Flowers said.

A reporter for public radio station WWNO was also arrested, the radio station said.

.@WWNO confirms that one of our reporters has been arrested in Baton Rouge. We have little information, and we are seeking more details. — 89.9 WWNO (@WWNO) July 10, 2016

Several hundred protesters took to the streets of San Francisco, blocking several roads and ramps to get on and off the Bay Bridge.

The California Highway Patrol closed access to the bridge at least two times Saturday afternoon when protesters took over freeway ramps, causing traffic to back up.

The group began marching from the city's Hall of Justice to the downtown shopping area, causing a temporary shutdown of a popular mall as the crowd gathered there to chant slogans and make speeches.

In central California, several hundred protesters blocked several intersections as they marched against police brutality in central Fresno. Officers in riot gear blocked an on-ramp to keep the protesters from entering State Route 41.

In Chicago, hundreds of protesters held demonstrations downtown Saturday, and a group attempted to disrupt the a city-sponsored food and music festival.

"No Justice, NO REVENUE," said a Facebook invitation to the demonstration, set to be held at "Taste of Chicago."

The festival was not closed, NBC Chicago reported. Protesters continued on a march and staged sit-ins and blocked intersections, the station reported.

The deaths of Sterling and Castile renewed scrutiny of the use of deadly police force on African-Americans. As a protest was underway in Dallas Thursday, a gunman who said he was upset at white people opened fire on police officers, killing five officers and wounding seven others in what officials described as a targeted attack. The gunman was killed by police.

Hundreds of people also marched in West Palm Beach and Fort Lauderdale Saturday as part of the Black Lives Matter movement in demonstrations that ended peacefully.

Protesters in Fort Lauderdale chanted "No justice, no peace" and "Hands up, don't shoot." At one point the protest stopped outside a Broward County jail and prisoners banged on windows in support, but the protest was largely calm.

"It's love out here. Everybody is happy and peaceful. It's not something that we are coming to tear another race down," a rally organizer told NBC Miami.

People take part in a protest against police shootings and in support of Black Lives Matter during a march in New York July 9, 2016. EDUARDO MUNOZ / Reuters

A protest march was also held in Philadelphia. "Clearly this is REVOLUTION time. We know this," an organizer wrote on Facebook.

Elsewhere in Pennsylvania, several hundred people broke off from Pittsburgh's 200th anniversary parade and marched to a courthouse to denounce the shootings of black men.

Protestors now arriving at 25th Philly Police district. @NBCPhiladelphia pic.twitter.com/pZ0A4BqM1m — Drew Smith (@drewsmithtv) July 10, 2016

More than 150 people also gathered in downtown Newport, Rhode Island, in support of the Black Lives Matter movement.

Seneca Pender of Middletown organized the rally. He told the crowd that the senseless killings of black people "have to stop."

Pender also thanked law enforcement officers who provided security at the rally in Newport and decried the deadly attack Thursday on police officers in Dallas.