An 18-year-old black man was shot and killed by police at a gas station late on Tuesday in a St. Louis suburb near where unarmed teen Michael Brown was killed by a white officer in August, police and local media said.

A live video feed showed the gas station cordoned off by yellow tape and lined by police officers, with bystanders shouting at them in a tense standoff.

The St. Louis Post-Dispatch newspaper reported that some 60 people had gathered at the scene and that at least three people were arrested. Images and video footage showed what appeared to be smoke and loud bangs, although it was not clear whether it was the bystanders or the police that had caused them.

Police said the man had pointed a handgun at an officer who approached him and another man at a gas station in the suburb of Berkeley.

"Fearing for his life, the Berkeley Officer fired several shots, striking the subject, fatally wounding him," St. Louis County Police Department spokesman Brian Schellmansaid in a statement. The second man fled the scene.

Berkeley is minutes away from the suburb of Ferguson, where police officer Darren Wilson shot Michael Brown, a killing that ignited protests across the country against police methods.

About 200 people marched in New York on Tuesday, defying Mayor Bill de Blasio's call for protests to be suspended after two police officers were killed in their patrol car on Saturday in an apparent revenge attack.

The St. Louis Post-Dispatch named the victim as 18-year-old Antonio Martin, citing his mother. The police said they could not confirm his identity.