Police in Missouri are on standby for any more trouble after violence broke out following the shooting of a black teenager by a white officer.

18 year-old Antonio Martin's death in a suburb of St Louis follows the killing of Michael Brown in the area in August.

Berkeley Mayor Theodore Hoskins has appealed for calm while the incident's examined:

The 18-year-old was killed at a Mobil petrol station in the St Louis suburb of Berkeley on Tuesday night.

Bricks are said to have been thrown at police in the aftermath of the shooting.

In a news conference St Louis County Police chief Jon Belmar said the officer was responding to a call about a theft at around 11.15pm when he saw two men and approached them.

He said after talking to the individuals, one of the men pulled out a 9mm pistol and pointed it at the officer.

Chief Belmar said the officer fired three shots and one struck the teenager.

No shots were fired by the suspect, who was identified by his mother to local media as Antonio Martin.

CCTV video from the car park appears to show the man pointing a gun at the officer.

Detectives said they recovered the dead man's weapon at the scene.

Chief Belmar said the victim was known to police and had previously been arrested for assault and armed robbery.