Police have released CCTV showing the moment before a black teenager was shot dead by a police officer in a killing which has sparked more violent protests in Missouri.
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.
Protest
Following the shooting, a crowd of up to 300 people gathered around the cordoned off forecourt.
A wall of police officers, some wearing riot helmets, guarded the scene with bystanders shouting at them in a tense standoff.
Footage showed fireworks being let off and some officers were injured after bricks were thrown.
Four people were arrested and there were also reports of others trying to break into local businesses.
Chief Belmar said he understood the emotions of the young people but that "bad choices were made" by the victim.
"This individual could have complied with the officer, he could have run away, he could have dropped the gun. All sorts of things could have happened. It didn't have to end with him approaching the officer with a 9mm pistol in his hand," he said.
He said the victim was dead when paramedics arrived but his body was not able to be removed until around 1.40am, over two hours after the shooting.
It is not known if the incident has been recorded on the officer's Dashcam and his body camera was not turned on at the time.
Martin's mother, Toni Martin was at the scene overnight where she was heard crying "That's my baby" when she found out that the victim was her son.
She told the St Louis Post-Dispatch that Martin had been out with his girlfriend.
"His girlfriend told me the police was messing with him. He was trying to get up and run and they started shooting.
Ms Martin said he was a "good young man" who was "trying to get his life back together" after being expelled from school.
She claimed her son was not carrying a gun.
Berkeley is the neighbouring suburb to Ferguson where an unarmed Michael Brown was killed by police officer Darren Wilson on 9 August.
Protests spilled over into violence when a grand jury decided not to charge Mr Wilson.
Demonstrations in cities across the country gained in momentum when a New York grand jury decided not to charge police over the death of Eric Garner, a 43-year-old black man whom police tackled and put in a chokehold.
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.
Originally posted at 9.39am
