Tear gas and arrests marked the first night of a state-imposed curfew in Ferguson, Missouri, after Gov. Jay Nixon declared a state of emergency in the city.
Five armored tactical vehicles approached a crowd of protesters who refused to disperse, as police warned them to leave or face arrest.
But the protesters chanted "No justice! No curfew!" and "We have the right to assemble peacefully."
Moments later, police fired canisters into the crowd.
Christian rapper and ex-gang member Travis Tyler, also known as Thi'sl, lives in St. Louis. He offered his take on the police shooting death of unarmed teen Michael Brown and the subsequent protests. Click for his comments.
Highway Patrol Spokesman Lt. John Hotz initially said police only used smoke, but later told The Associated Press that they also fired tear gas canisters.
"Obviously, we're trying to give them every opportunity to comply with the curfew," he said.
Earlier this weekend, hundreds of protesters clashed with police again in Ferguson, Missouri, after authorities identified the white officer who shot a black teenager more than a week ago.
Police say officer Darren Wilson shot and killed Michael Brown, 18, after he had been accused of robbing a convenience store August 9. Wilson said he was assaulted during the scuffle and had to be taken to the hospital for facial injuries after the incident.
Authorities are still investigating exactly what happened before Brown was killed. On Friday, Ferguson Police Chief Thomas Jackson released documents alleging that Brown stole a $48.99 box of cigars from the convenience store, then strong-armed a man on his way out.
Brown's death had previously ignited four days of clashes with furious protesters. Tensions eased some on Thursday after Gov. Jay Nixon replaced the city's local police presence with the state Highway Patrol.
"I know that Ferguson will not be defined as a community that was torn apart by violence," Gov. Nixon said.
By Friday, tensions boiled over again as angry protesters stormed the convenience store where Brown was shot. Some began throwing rocks and other objects at police, hurting at least one officer.
Missouri State Highway Patrol Capt. Ron Johnson said police backed off to try and ease the situation.
"We had to evaluate the security of the officers there and also the rioters," he said. "We just felt it was better to move back."
At the same time, peaceful protesters eventually blocked off the front of the store to help protect it from looters.
'Main Street No Place for M16s'
Meanwhile across the country, many are criticizing Ferguson's military-like approach to policing protesters as outrageous, with some blaming the U.S. government.
Through a program called 1033, the Pentagon offers hundreds of millions of dollars of surplus military equipment to police forces throughout the country. St. Louis County, which encompasses Ferguson, is part of the program.
According to USA Today, county law enforcement agencies received twelve 5.56 millimeter rifles and six .45 caliber pistols from the Department of Defense between August 2, 2010 and February 13, 2013.
Lawmakers are calling for an end to the program. Rep. Hank Johnson, D-Ga., plans to introduce legislation to curb it,
"Our Main Streets should be a place for business, families, and relaxation, not tanks and M16s," Johnson said Thursday. "Militarizing America's Main Streets won't make us any safer, just more fearful and more reticent."
Libertarian Sen. Rand Paul, R-Ky., shared Johnson's opinion.
"The militarization of our law enforcement is due to an unprecedented expansion of government power in this realm," he said.