The young man was shot dead by police while being served a search warrant. Racial tensions remain high after several black men have died at the hands of law enforcement.
St. Louis police launched tear gas and detained nine people after protests became violent early Thursday morning, officials said. The arrests were announced from the police department's Twitter account.
The demonstrations began shortly after an 18-year-old black man was shot in a confrontation with white police officers, according to the St. Louis Post Dispatch. Constables were serving a search warrant to Mansur Ball-Bey when the suspect allegedly pulled a gun. Police then opened fire, killing the youth.
The city's Police Chief Sam Dotson said protestors refused to clear a street, instead throwing bottles and bricks at law enforcement. Officers reacted by throwing teargas at the crowd.
"Peace was restored after a total of nine arrests," he told reporters at a press conference.
Residents of the neighborhood reported burglaries and torched vehicles later in the evening.
"A group of protesters came together and started to do acts of violence directed not only towards law enforcement but towards the neighborhood," Dotson said in recorded remarks released by the police department.
According to Dotson, three stolen guns were found in the home of Ball-Bey following his death.
One of the city's suburbs, Ferguson, has been the epicenter of protests against what is perceived as racial profiling and police violence toward black people by white policemen.
Ferguson was the site of a peaceful demonstration earlier this month to mark one year since the shooting of Michael Brown, an unarmed black teenager, after an officer said the 18-year-old had threatened him.
The incident launched a renewed discussion on race and policing practices in the United States, leading to the White House to review police and racial equality initiatives.
The white police officer charged in the death of Michael Brown was never indicted and cleared of any wrongdoing.
kb/jil (AFP, dpa)