Police disperse Missouri protesters

Police used smoke bombs and tear gas to disperse demonstrators who defied a curfew in Ferguson, Missouri, early on 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 on Saturday until 5 am for the St. Louis suburb of Ferguson, where 18-year-old Michael Brown was shot dead by a white police officer on Aug 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 disperse, 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 at about 3:50 am.

"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.