ST. LOUIS — Officers arrested at least nine people and deployed tear gas amid protests in St. Louis over the death of a black 18-year-old who was fatally shot by police after he pointed a gun at them, the city’s police chief said.

Chief Sam Dotson said at a news conference late Wednesday that a group of protesters who had blocked an intersection threw glass bottles and bricks at officers and refused orders to clear the roadway. Inert gas was used and when that had no effect on the crowd, police used tear gas to clear the intersection, Dotson said. Those arrested face charges of impeding the flow of traffic and resisting arrest, he said. A vacant building and at least one car were burned.

The demonstration was one of several Wednesday after the killing of 18-year-old Mansur Ball-Bey of St. Louis. Tensions were already high after violence erupted during events marking the anniversary of the death of Michael Brown, the 18-year-old fatally shot last year by a police officer in nearby Ferguson.

Two police officers serving a search warrant encountered two suspects Wednesday afternoon at a home in a crime-troubled section of the city’s north side, one of which was Ball-Bey, the chief said.