Ferguson, Missouri, has seen a week of unrest as riots flared up in response to the shooting dead of an unarmed black teenager by police.
Anger remains high over the death of Michael Brown, 18, shot on 9 August in the mainly black suburb of St Louis.
On Saturday, an overnight curfew was imposed in Ferguson in an attempt to stem the riots.
Police broke up a crowd of at least 150 people who gathered in defiance of the curfew. One person was said to be in a critical condition after a shooting incident near Red The Man's BBQ.
Police said they moved in after receiving a report of people breaking into the restaurant and climbing on to the roof.
Police also deployed smoke bombs and tear gas in an attempt to disperse the crowd.
Police said that seven people had been arrested in further unrest on Saturday night but not in connection with the curfew.
The confrontation ended nearly an hour after the midnight curfew went into place.
Earlier in the week, shops in Ferguson were looted by rioters and the owners have since boarded up their windows.
