Antonio Martin pepper spray crowd
The unidentified man (above) was a member of a crowd that gathered after Antonio Martin was shot dead by a police officer in Berkeley, Missouri near Ferguson. Stackizshort Ustream live feed

Onlookers have been left reeling after police pepper-sprayed a number of people following the shooting of black teenager Antonio Martin in Berkeley, Missouri.

A large crowd gathered following the shooting of 18-year-old Martin, prompting police to deploy riot squad officers. They have yet to ask the crowds to move away.

The image above, taken from a live video stream from user Stackizshort on Ustream, shows a man who claims he was maced by officers near the petrol station forecourt.

The shooting

The incident took place near the flashpoint town of Ferguson where teenager Michael Brown was killed by officer Darren Wilson earlier this year.

The teen was reportedly killed outside the Mobil gas station in the town and social media users posted photos and footage of Martin's mother at the scene.

Initial reports from witnesses suggest that Martin was unarmed while others claim that a gun was found at the scene. Whether Martin was armed or not at the time of the incident could be immediately verified.