Missouri National Guard troops were deployed yesterday to the St Louis suburb of Ferguson to try to restore calm to an area that has become a nightly scene of rioting and protests over the August 9 fatal shooting of an unarmed black teen by a white police officer.
Missouri Governor Jay Nixon's move to bring in the guard troops follows his declaration on Saturday that the area was in a state of emergency and the setting of a curfew calling for the streets in Ferguson to be cleared after midnight.
President Barack Obama was meeting with Attorney General Eric Holder to discuss the Ferguson situation,his office said.
Both the US Department of Justice and St Louis County Police are investigating the shooting of Michael Brown (18).
Each night since the teen was killed, protesters have been walking the streets in and around the neighbourhood where he was shot. The demonstrators have been holding signs, chanting slogans and calling for the arrest of Darren Wilson (28), the officer who shot Brown.
Schools in the area were ordered closed because of the chaos in and around the town of roughly 21,000 mostly black residents.
Brown's mother, Lesley McSpadden, spoke gave a televised interview with ABC's Good Morning America programme, saying peace could be restored "with justice... arresting this man and making him accountable for his action."
Her family's lawyer, Benjamin Crump, said on the same programme that autopsy results that show Brown was shot six times, including twice in the head, were "very troubling."
"It's just not justified in any way, fashion or form to execute this child," Crump said.
The Brown family has called for peaceful demonstrations and an end to violence, and the police forces on the ground have been widely criticised for using excessive force on protesters.
But police say a few of the thousands who have gathered have thrown petrol bombs and shot at them.
Governor Nixon and other law enforcement officials have said that they have to use force to stop looting that has hit several businesses and attacks on police.
On Sunday night, police wearing gas masks and body armour fired tear gas and smoke canisters hours ahead of the curfew, which ran on Saturday and Sunday from midnight to 5am. The Missouri Highway Patrol said "aggressors" tried to infiltrate a law enforcement command post.
"Coordinated acts" by a few in the crowd were "premeditated criminal acts designed ... to provoke a response," State Highway Patrol Captain Ron Johnson told a late-night news briefing. "I had no alternative but to elevate the level of our response."
Johnson said the trouble on Sunday night had begun after police responded to the shooting of a civilian at 8.25pm.
Gunfire was directed toward police, and petrol bombs were thrown. At least one other person was shot, and several were arrested. No police were injured.
A preliminary private autopsy, requested by Brown's family, showed the teenager was shot at in the arm, neck and head.
Holder has ordered a federal autopsy of Brown's body, seeking to assure the family and community there will be a thorough investigation.
Police have given few details of Wilson's version of the account. The officer remains in hiding, and police say he has been threatened.
According to police, Brown and a friend were walking down the middle of a road that runs between some apartment complexes when Wilson asked the two to move off the road and on to a sidewalk.
They said Wilson said Brown reached into a patrol car and struggled for his service gun when Wilson fired the initial shot.
Brown's friend Dorian Johnson (22)and at least one other witness said Wilson had reached out through his car window to grab at Brown and that the teenager was trying to get away when he was shot.
Brown held up his hands in a sign of surrender but Wilson got out of his patrol car and shot him several more times, they said.