The US police officers fired stun grenades into a crowd and arrested reporters in a third night of chaos in the aftermath of the police shooting of Michael Brown, an 18-year-old high school graduate.
Police also used smoke bombs after directing people to go home. Helicopters circled overhead and smoke hung in the air, AP reported.
St. Louis County police spokesman Brian Schellman said he had no immediate information about the situation.
Since Saturday, the shooting of Brown has sent hundreds of residents from the St Louis suburb of Ferguson into a heated confrontation with police.
In the meantime, yet another unarmed African-American man were shot dead by Los Angeles police.
The mother of the 24-year-old deceased man said her son was lying on the ground and complying with police commands when Los Angeles police shot him three times, Press TV reported.
The fatal shooting took place on Monday night as officers conducted an investigative stop, according to a LAPD statement. During that stop, "a struggle ensued" and this resulted in an "officer-involved shooting," according to the statement.