FERGUSON, USA (AFP) – Police used smoke bombs and tear gas to disperse demonstrators who defied a curfew in Ferguson, Missouri early Sunday, where a fatal police shooting of an unarmed black teen triggered a wave of rioting.

Missouri Governor Jay Nixon declared a state of emergency and a curfew starting at midnight Saturday (0500 GMT Sunday) until 5:00 am for the St. Louis suburb of Ferguson, where 18-year-old Michael Brown was shot dead by a white police officer on August 9.

Ferguson was mostly peaceful when the curfew began on Sunday, but a crowd of protesters gathered in the area where Brown was shot and refused to disperse.

Riot police, backed up by reinforcements in armored vehicles, hurled smoke and tear gas canisters and slowly moved in to break up the crowd, which local media said numbered around 200.

Seven people were arrested for failing to dispurse, said Missouri Highway Patrol Captain Ron Johnson, the African-American officer that governor Nixon put in charge of restoring peace in Ferguson.

Johnson said that police moved when they received reports that someone apparently unrelated to the protests had been shot, and that armed individuals had broken into a restaurant.

“We have a shooting victim in critical condition that may lose her life,” said Johnson, speaking to reporters around 3:50 am (0750 GMT).

“We had a subject standing in the middle of the road with a handgun. We had a police car shot at tonight. And, yes, I think that was a proper response tonight, to maintain officer safety and public safety.”

Antonio French, an area politician who was with the protesters when police moved in, wrote that some were ready for violence.

“I can tell you firsthand that some of the people that remained tonight were armed. Were ready for a fight. And wanted to injure police,” he wrote on Twitter.

He also wrote: “It’s important to differentiate the protestors from those violent opportunists that are not thinking about #MikeBrown or justice. #Ferguson.”

Governor Nixon said he ordered the emergency measures “to protect the people and property of Ferguson” after looters raided town stores and scuffled with police overnight Friday to Saturday.

Nixon, speaking at a press conference Saturday held at a local church, was repeatedly interrupted by locals angered by an apparent lack of accountability for the largely white police force responsible for Brown’s death in the majority black area.

“Excuse me, governor, you need to charge that police officer with murder,” said a heckler, referring to the white officer who shot Brown. “Yeah!” cried out supporters.

“Call for an investigation,” said another heckler, as palpable anger and frustration simmered in the church hall. “Where’s the indictment?”

Riot police fired tear gas and clashed with looters in the early hours of Saturday, after police named Brown as a suspect in the robbery of a Ferguson convenience store.

Gangs of thieves targeted several stores, including the one that Brown allegedly robbed just before he was shot dead on August 9.

Protesters also hurled Molotov cocktails and bricks at police, who responded with tear gas, smoke bombs and rubber bullets but they mostly stayed at a distance in armored vehicles and riot gear.

In some cases locals locked arms outside stores to keep looters out, and in others store owners showed up carrying rifles and sidearms to protect their property.

On Saturday afternoon, hundreds of people gathered peacefully near the scene of Brown’s shooting, marking the exact moment he was shot a week earlier.

Brown’s death has renewed a national debate about relations between law enforcement and African Americans.

His family appealed for calm, but accused authorities of a “devious” attempt to smear their son’s character after police released surveillance video of the store robbery.

The video shows a young black man carrying cigars out of a convenience store, and pushing another man who tries to stop him.

The robbery occurred just minutes before the policeman shot Brown dead, but police said the officer stopped the teen for walking in the middle of the street and did not know of the robbery.

In Harlem, New York, African American civil rights activist Al Sharpton criticized the video’s release, accusing the police of sullying Brown’s image in the public eye.

“Have we lost our decency when you don’t even let people mourn their loved ones without you trying to smear them with things that have nothing to do with the situation?” he asked.

“Are you telling me that you have the right to run down somebody and kill him over three or four cigars?”

Police identified the officer who shot Brown as Darren Wilson, 28, a white, four-year veteran of the force with no disciplinary record.