Seven people have been arrested after police in Missouri used smoke and tear gas to impose a curfew in a suburb where a black teenager was shot dead by an officer.

In the latest protest, one man has been hit by a bullet fired by someone in the crowd.

A state of emergency has been declared in Ferguson following days of riots and protests.

18 year-old Michael Brown was unarmed when he was shot a week ago.

Captain Ron Johnson, who is leading the security operation in Ferguson, says he feels police responded in an appropriate manner:

"We have a shooting victim that’s in critical condition that may lose their life.

"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."