US police made numerous arrests during a tense night-time standoff in Ferguson, after St. Louis County declared a state of emergency and a teenager was charged with shooting at police officers.
Protesters on the streets beat drums and chanted as bottles and rocks were thrown, while cops used pepper spray as they detained demonstrators during the standoff, which continued into the early hours of Tuesday morning.
"Officers are being hit with rocks and bottles. We continue to support free speech, but agitators who ignore orders to disperse risk arrest," tweeted the St. Louis County police department.
The protests came after unrest and a shootout in Ferguson Sunday night that led county officials to declare a state of emergency Monday.
St. Louis County executive Steve Stenger said county police would immediately take charge of "police emergency management" in Ferguson and surrounding districts.
"In light of last night's violence and unrest in the city of Ferguson, and the potential for harm to persons and property, I am exercising my authority as county executive to issue a state of emergency, effective immediately," he said in a statement.
His statement was issued as an 18-year-old was charged in connection with the shootout in Ferguson on Sunday, following a day of mostly peaceful protests marking the first anniversary of the fatal police shooting of unarmed black teenager Michael Brown.
Tyrone Harris is accused of first-degree assault on police officers, armed criminal action and shooting at a motor vehicle, police said.
Harris, from Northwoods, another section of St. Louis County, remained in the hospital Monday with wounds sustained in the shootout.
In St. Louis city center, more than 50 protesters were arrested after climbing the barricade around a federal courthouse during a midday demonstration, local news media reported.
Media reports late Monday said protesters had blocked a main highway, Interstate 70, just outside Ferguson. Demonstrators were also arrested elsewhere in town, including scholar and activist Cornel West, Complex magazine reported.
Early Tuesday morning a crowd of about 100 protesters remained on the streets of Ferguson.
Sunday's day of remembrance for Brown had been peaceful until a handful of protesters grew rowdy later in the evening.
The gunfire followed the looting of at least two Ferguson businesses, on a commercial strip around the corner from where Brown fell.
"I think it's unfortunate that a beautiful day of events ended like that," said Dellena Jones, whose hair salon was among the shops hit.
"Some people broke in to some of the businesses on our lot, and so we are all here helping each other," she told AFP, adding that her shop had been turned into "a wreck".
Attorney General Loretta Lynch strongly condemned Sunday's violence, as she spoke Monday at a police union convention in Pittsburgh, Pennsylvania.
"Not only does violence obscure any message of peaceful protest, it places the community, as well as the officers who seek to protect it, in harm's way," she told the Fraternal Order of Police gathering.
St. Louis County Police Chief Jon Belmar said the shootout started when four plainclothes detectives in a van came under fire.
AFP video showed a black man lying face down on the ground in handcuffs, bleeding profusely. Belmar declined to comment on the race of the detectives.
Outrage over the police killings of Brown and other unarmed African Americans has been channeled into a sustained nationwide movement, with the social media hashtag #BlackLivesMatter becoming its rallying cry.