Weeks after protests over the shooting of unarmed black teenager Michael Brown started to subside, police in another St. Louis suburb have reportedly shot and killed an 18-year-old black man at a gas station, according to the St. Louis Post-Dispatch.

A large crowd of about 100 people started to form at the scene of the Mobil gas station in Berkeley, Missouri after 18-year-old Antonio Martin was shot shortly after 11 p.m. on Tuesday, the Associated Press reports.

The crowd eventually grew to be 200 to 300 people, according to the Post-Dispatch. Four people were arrested for allegedly assaulting officers.

St. Louis County Police released a statement saying Martin was shot after he pulled a gun and pointed it at an officer as he approached Martin outside the gas station. The officer who shot Martin is white and has been with the Berkeley police department for six years.

"Fearing for his life, the Berkeley officer fired several shots, striking the subject, fatally wounding him," the earlier statement said.

The officer who killed Martin fired three shots, St. Louis County Police Chief Jon Belmar said at a press conference. Martin was reportedly struck by one bullet.

Police have not confirmed Martin's name, but a woman at the scene overnight identified him as her son.

A second person reportedly fled the scene. Police say they have recovered the gun they say belonged to Martin, who was reportedly known to authorities. An investigation into the incident is ongoing.

Police have released surveillance video from the gas station that shows part of the incident.

Protests grew and continued overnight. Those on scene have reported seeing bricks thrown, police cars being attacked, and pepper spray being used. Some police on the scene are reportedly clad in riot gear, according to the AP. A QuikTrip store near the scene of the shooting was vandalized during the protests.

Berkeley is just a few miles from Ferguson, where unarmed black teenager Michael Brown was shot and killed by white police officer Darren Wilson in August. Some demonstrators at the Berkeley gas station were also reportedly active in the Ferguson protests.

Racial tensions in St. Louis reached a boiling point after Brown's shooting, with violent protests breaking out in and around the city.

At some point during the Berkeley protest, a flash device was detonated:

Here's a look at the crowds on scene in Berkeley:

Current scene in #Berkeley 63134 police shooting of #Antonio Martin 18 Frost & Hanley pic.twitter.com/HxKT07uL2o — Search4Swag (@search4swag) December 24, 2014

Police are trying to block our view of them placing #AntonioMartin's body in a SVU. People have broken through tape! pic.twitter.com/RpyFsqpdY0 — Charles Wade (@akacharleswade) December 24, 2014

#AntonioMartin mother is breaking down badly again. #AnthonyShahid and protesters with the family. pic.twitter.com/gpl4LZac17 — Charles Wade (@akacharleswade) December 24, 2014

A reporter for the St. Louis Post-Dispatch notes that a gun is at the scene with an evidence marker near it: