CNN video showed police in riot gear moving down East Fourth Street, a strip of restaurants, and pushing back protesters. The officers yelled, "Move back!" in unison as they advanced.
A CNN crew saw at least 15 people being taken into custody by police in riot gear, accompanied by troopers. They were loaded into vans and taken away.
Multiple arrests were made at East Fourth Street because of "unlawful behavior by large crowd," another tweet said. Police appeared to greatly outnumber protesters.
Protesters took to the street immediately after Judge John P. O'Donnell acquitted Officer Michael Brelo on charges of voluntary manslaughter and felonious assault.
The crowd assembled outside the judicial center in Cleveland for two hours following the announcement of the verdict.
Some chanted "no justice, no peace" and "black lives matter," words heard in Ferguson, Missouri, and New York, where sometimes-violent demonstrations occurred after African-Americans died at the hands of white police officers.
Law enforcement officers formed a line and kept them from entering the judicial center. The protesters marched through parts of the city. Some formed a line on the Cleveland Memorial Shoreway, a freeway through town, and blocked traffic briefly.
As a precaution, two schools, Shaker Heights High School and St. Ignatius High, relocated their weekend proms out of downtown, CNN affiliate WOIO reported.
Brelo, 31, was accused of firing the bullets that killed Timothy Russell, 43, and Malissa Williams, 30, on November 29, 2012, after a 22-mile police chase ended in a middle school parking lot. Authorities said Brelo stood on the hood of the car Russell was driving and fired 15 shots through the windshield.
Though about a dozen officers fired a total of 137 rounds at the car, no other officers were charged with manslaughter.
In explaining his verdict, Judge O'Donnell said
it was reasonable for Brelo to think Russell and Williams still posed a threat to officers. The chase started after the car driven by Russell backfired -- a noise officers mistakenly thought was caused by gunshots. The judge also said he couldn't be sure Brelo fired the fatal rounds.
Relatives of the slain citizens had harsh words for police and the court system Saturday.
"We were expecting him to be convicted of at least one of the charges," said Jackie Russell, sister-in-law of Timothy Russell, said on CNN. "We feel as though basically the judge gave him a pat on the back and said good job for shooting those people."
"If this case was tried in any other city that police (officer) would be in jail," said Alfredo Williams, brother of Malissa Williams. "You know it and I know it."
Michelle Russell, Timothy Russell's sister, said nobody will know why her brother didn't stop when police pursued.
"I know that those officers were upset," she said. "Adrenaline was flowing. By the time they cut off Tim and Malissa in that parking lot, they let them have it."
The family later released a statement.
"The judge began the explanation of his ruling by pointing to the countless instances across the nation where racialized policing has occurred and resulted in the untimely deaths of Black and Brown women, men and children. Even as Judge O'Donnell acknowledged the disproportionate killing of people of color, he failed to hold Officer Michael Brelo accountable for his reckless and cruel actions," a line read.
Social media buzzed with reaction, mostly against the verdict.
@dontahenson tweeted, "If 4 civilians shoot 137 rounds and kill 2 people, everyone gets charged with murder. Cops, no so much. #BreloVerdict"
@MichaelEDyson tweeted, "So because we can't determine that this cop killed the victims in a hail of bullets, then none of them is therefore guilty? #BreloVerdict."
Tom Fuentes, a former FBI assistant director, told CNN that he thinks people are upset because of the enormity of the police response.
"A lot of the outrage of this case is that over 100 shots, that many police officers, that many police officers involved in the pursuit was clearly excessive," he said. " And i think any reasonable police officer would agree that in totality it was excessive. But the totality wasn't on trial. It was one cop firing the shots he fired at that car with the belief that possibly there was still a situation where his life might be in jeopardy."
City officials -- and Cleveland Cavaliers star LeBron James -- called for calm.
"Violence is not the answer and it's all about trying to find a solution," James told WOIO.
He hoped the Sunday game in the NBA playoffs against the Atlanta Hawks would calm people down. "I think sports is one of the biggest healers in helping a city out," he said.
Police Chief Calvin Williams said at a press conference, "We're going to do everything humanly possible to keep the city safe. The city will not tolerate any violence or destruction."
"Today's verdict is the first of several complex policing and community issues that will test Clevelanders in the days, weeks, and months ahead," said Mayor Frank G. Jackson. "We will show the nation that peaceful demonstrations and dialogue are the right direction as we move forward as One Cleveland."
Brelo's lawyer, Patrick D'Angelo, said authorities went too far in charging his client at all.
"The prosecution in this case spared no expense and was, in fact, ruthless," he said. "We fought tooth and nail, as you saw in the courtroom. It was classically a case of David vs. Goliath."
Cleveland has avoided violent protests so far, despite several incidents that raised concerns about excessive use of force by police. A 2014 Department of Justice report that found that Cleveland police had a pattern of using excessive force.
On Saturday, a protest was held to demand action in the death of Tamir Rice
, a 12-year-old boy shot last November by a Cleveland police officer, according to CNN affiliate WEWS.
The event had been scheduled before the Brelo verdict was announced.
About 200 people carried a coffin from a park to the home of prosecutor Timothy McGinty, WEWS reported. No charges have been filed in that killing, though Sheriff Clifford Pinkney recently said the investigation of the case is almost finished.
"We just want the prosecutor to follow suit with what happened in Baltimore," said Malaya Davis, with The Ohio Student Organization. "It only took a few weeks for the prosecutor to charge all officers involved."
Six Baltimore officers have been charged
in the death of Freddie Gray
. His death sparked days of unrest in Baltimore.
Darren Toms, the Cuyahoga County Courthouse spokesman, said authorities tried to release the Brelo verdict at a time that would cause the least disruption. He sent this statement:
"The decision to announce the verdict in this high-profile case on a holiday weekend was not made lightly. It was done so following consultation between the Court administration, other court officials, and the local law enforcement community.
"The prime consideration was to not delay the reading of the verdict any longer than necessary. While the wait was difficult for many, it was especially hard on the parties involved in the case and their families. Once Judge O'Donnell reached his verdict and finished writing his opinion, he and the Court wanted to let the parties know the decision as quickly as possible.
"It was agreed that by announcing it on a Saturday morning, the potential for downtown traffic issues and the resulting impact on the community could also be lessened."