Protesters smashed the windows of dozens of businesses and threw objects at police near St. Louis in a second night of violence after the acquittal of a white former policeman in the shooting of a black man.
The confrontation took place late Saturday night in the Delmar Loop area of University City, a suburb about 10 miles (16 kilometres) west of St. Louis. The area is known for restaurants, shops and bars.
A few dozen protesters refused to disperse after a non-violent march. Hundreds of police in riot gear moved in. The demonstrators retreated down a street, vandalizing businesses.
City and county police say they made at least nine arrests. At least one demonstrator was treated after he was hit with pepper spray.
Demonstrators are expected to reconvene near St. Louis Sunday afternoon for a third day of protests.