Protests simmered for the fourth straight day Monday in St. Louis, Missouri, amid outrage over the acquittal of a white former police officer in the shooting death of a black man.
Dozens marched peacefully, some carrying "Black Lives Matter" signs, through the Midwestern city's downtown streets and in front of city hall, while some 250 high school students also briefly marched out of school.
Police said there were no arrests or incidents, after a weekend in which dozens were arrested as largely peaceful protests turned violent three days running.
"The days have been calm and the nights have been destructive," St. Louis Mayor Lyda Krewson said Monday in an early morning news conference.
The public outcry is over a judge's ruling Friday that there was not enough evidence to convict former police officer Jason Stockley of murdering Anthony Lamar Smith, a black man, following a 2011 car chase.
Protesters have marched through city streets, clashed with police, thrown bricks through the windows of businesses and overturned trash cans.
The violence led to the cancellation of several cultural events over the weekend — including concerts by rock giant U2 and pop star Ed Sheeran.
Police suffered minor injuries and responded with force, appearing in riot gear and arresting protesters. Police reported more than 80 arrests Sunday.
"Once again, a group of criminals set out to break windows and destroy property. Tonight, those criminals are in jail," acting police chief Lawrence O'Toole said.
"Some criminals assaulted law enforcement officers and threw chemicals and rocks at them."
But activists and observers fired back on social media, claiming police have been aggressive towards protesters.
They also taunted reports of confiscated chemicals, claiming the substances were merely apple cider vinegar used to counteract weapons such as pepper spray.
Among those arrested was a journalist for the St. Louis Post-Dispatch newspaper, who was caught up with a crowd as police corralled people who they said had not complied with orders to disperse.
"We are closed in on all four sides now I have no idea where people are supposed to go. People freaking out," Mike Faulk wrote in one of his final dispatches on Twitter prior to his arrest.
Journalists for the newspaper said editors had been trying to find Faulk after his arrest. He was not released until Monday afternoon.
The American Civil Liberties Union criticized the St. Louis police response, saying officers have at times acted illegally.
"From eyewitness and filmed accounts, we continue to see the St. Louis Metropolitan Police Department engage in unacceptable, unlawful and unconstitutional behavior," the civil rights group said Monday.
The ACLU claimed an officer dangerously drove a police car backwards into a crowd, and that other officers used excessive force and unlawfully detained people.
"We urge everyone to ask themselves a bigger question: Why are these protests happening?" the ACLU said.
Stockley's acquittal was the latest example of the difficulty US prosecutors face in charging law enforcement officers following controversial deaths of citizens.
A number of cases brought against officers in various US cities have failed to send officers to jail — including in the nearby states of Minnesota, Ohio and Wisconsin.
St. Louis has a history of tension between police and its black communities. The city and its suburb Ferguson became the focus of national attention following the 2014 police killing of Michael Brown, which sparked protests and disturbances.
Brown, an 18-year-old African American, was shot to death by white Ferguson police officer Darren Wilson.
Wilson was not charged by local or federal prosecutors, but the incident led to a Justice Department investigation that found a pattern of civil rights violations by the Ferguson police.
Eric Holder, President Barack Obama's attorney general, concluded that Ferguson police "routinely violate" constitutional rights, including unjustified arrests and unreasonable use of force.