Tyrone Harris, who was shot by Ferguson police during events marking the first anniversary of the killing of unarmed black teenager Michael Brown, has been charged with assaulting officers, prosecutors say.
Tyrone Harris, 18, was critically wounded in a gun battle with police on August 9.
The authorities have declared a state of emergency in Ferguson, Missouri.
Michael Brown’s death triggered a wave of demonstrations over the use of excessive police force by officers.
The 18-year-old was shot in August 2014 by white police officer Darren Wilson, who was later cleared of any wrongdoing by a grand jury and the DoJ.
On August 10, some 50 people were shown on local news networks being arrested after blocking the main courthouse in St Louis, including civil rights activist Cornel West.
Rallies were due to take place in parts of St Louis and other major US cities as part of a day of civil disobedience called by activists.
Hundreds of people stood silent on August 9 for four-and-a-half minutes at the spot where Michael Brown was killed in Ferguson, representing the number of hours that his body lay in the street unattended.
However, the day of peaceful and somber commemorations turned violent late at night when, according to police, a gunfight erupted between two rival groups on West Florissant Avenue.
Police say Tyrone Harris was armed and opened fired, but his father has described their account of events as “a bunch of lies”.
Prosecutors filed 10 counts of charges against him, including assaulting an officer.
Police said Tyrone Harris was among six people who fired at an unmarked SUV with plainclothes detectives inside, who then fired back.
Tyrone Harris’ father told the AP news agency that his son, a close friend of Michael Brown, was shot between eight and 12 times as he was running away.
The gunmen “were criminals; they weren’t protesters,” he said, adding that the officers were not wearing body cameras – a major concern cited by protest groups.
Four police officers have been placed on administrative leave.
Photos from the scene showed a young black man lying bloodied on the ground. He was face down and handcuffed.
Announcing a state of emergency on August 10, the authorities in St Louis county placed police chief Jon Belmar in charge of Ferguson and the surrounding areas.
US attorney Loretta Lynch denounced the incident on Sunday, saying “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”.
It also drew criticism from protest groups, including the Ferguson Action Council and Organization for Black Struggle which described the police response as “excessive”.
John Gaskin III, a member of US rights group NAACP, told AP he did not expect unrest to escalate in Ferguson in the same way it has over the past year.
However, he warned, not many people would believe the police officers’ account of Sunday night’s events as “there’s still a tremendous level of distrust between law enforcement and the community”.
There have been a number of high-profile shootings of unarmed black men in US cities in recent months.
The most recent case involved 19-year-old Christian Taylor who was shot dead by a white police officer after he was spotted on surveillance footage vandalizing cars in Arlington, Texas, on August 7.
A man, who was later named as Tyrone Harris, was shot by Ferguson police at the protest to mark the first anniversary of the killing of unarmed black teenager Michael Brown.
Ferguson police said the man had opened fire on them and now is in a “critical, unstable” condition and due to have surgery.
Police also said he was armed with a stolen gun and they had been tracking him. Four officers have been placed on administrative leave.
Photos from the scene showed a young black man lying bloodied on the ground.
He was face down and handcuffed. In a video posted on Twitter, a man can be heard urging the police to “please, get him some help”, as the injured man lies still.
The wounded man’s name and age have not been released by police.
The St Louis Post-Dispatch identified him as 18-year-old Tyrone Harris, having spoken to his father, the paper said.
The shooting of 18-year-old Michael Brown in Ferguson by white police officer Darren Wilson in August 2014 sparked demonstrations across the US.
It fuelled a national protest movement against racial bias by police officers.
Shots were heard at about 23:15 local time on August 9 as a large crowd gathered on West Florissant Avenue, at the end of a sombre, peaceful day of commemorations.
St Louis County Police Chief Jon Belmar told reporters that after “an exchange of gunfire between two groups” the suspect, believed by police to be armed, left and encountered officers in an unmarked SUV.
The suspect fired on the vehicle, Jon Belmar said, and the plainclothes detectives returned fire from inside the van.
There was then a further exchange of fire after the officers left the vehicle.
The officers were not wearing body cameras, he added.
President Barack Obama announced a federal program to help pay for lapel-mounted cameras for US police to record their interactions in the wake of the nationwide protests on perceived policing injustices.
In the early hours of the morning, police used loudspeakers to urge people still gathered at the scene to disperse, saying “this is no longer a peaceful protest”.
Before this incident, hundreds of people stood silent for four-and-a-half minutes at the spot where Michael Brown was killed, representing the number of hours that his body lay in the street unattended.
Police officers in Ferguson, Missouri, are now wearing body cameras after weeks of unrest over Michael Brown’s killing.
Michael Brown, 18, was shot multiple times by Ferguson Police Officer Darren Wilson on August 9, sparking nearly three weeks of angry protests in the St. Louis suburb and drawing global attention to race relations in the US.
Law enforcement and witnesses gave differing accounts of what transpired before Michael Brown was shot, with police saying the teen had struggled with the officer. Witnesses say Michael Brown held up his hands and was surrendering when he was shot multiple times in the head and chest.
The discrepancy has revived calls for officers across the county to be outfitted with body cameras to help capture an accurate record of police-involved incidents.
Police officers in Ferguson are now wearing body cameras after weeks of unrest over Michael Brown’s killing (photo AP)
The policy has the support of scores of law enforcement agencies and the American Civil Liberties Union. Opponents say the cameras could be an invasion of privacy and deter people from approaching police with a tip.
During protests on Saturday, Ferguson officers began wearing small body cameras clipped to their uniforms that recorded crowds, conversations and even some taunts by demonstrators, a police official said on Sunday.
Ferguson Police Chief Tom Jackson told the St. Louis Post-Dispatch the cameras have been well received by officers.
The cameras were donated by two video surveillance companies, Safety Visions and Digital Ally. In a statement on its website, Safety Vision said it donated the cameras in the hopes that they could bring transparency to future investigations.
“The city of Ferguson has gone through an unfortunate series of events and Safety Vision body cameras and flashlight DVR will assist in capturing prima facie evidence for investigations involving vandalism, looting, and shots fired,” the statement said.
Some stores were looted in nightly protests, and police responded with riot gear and moved in military equipment to try to quell the turmoil.
A St. Louis County grand jury has begun hearing evidence about Michael Brown’s killing and the US Justice Department has opened its own investigation.