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Police have shot dead a black teenager in St. Louis, Missouri, sparking immediate protests that threaten to reignite long-running unrest over the officer killing of Michael Brown just two miles away.
The teenager, identified by local media as 18-year-old Antonio Martin, was shot at a gas station Tuesday night in the St. Louis County suburb of Berkeley. St Louis County police said he pulled a gun on an officer.
Protesters quickly descended on the scene and scuffles ensued as police tried to control the surging crowd, with officers reportedly throwing smoke bombs and stun grenades. The area has since been sealed off, but a crowd of around 100 demonstrators gathered nearby on Wednesday morning.
The nearby suburb of Ferguson saw large scale protests, often turning violent, in the wake of the Brown killing in August. Unrest surged again in November after a grand jury decided not to charge the officer, Darren Wilson, over the death of the unarmed teenager.
Another death at police hands, of New Yorker Eric Garner, who died when a white officer used chokehold a chokehold on Staten Island in July, has also drawn mass protests across the United States.
Unlike in those cases, the man shot on Tuesday night was armed, according to police accounts.
Police spokesman Sgt. Brian Schellman said in a statement that the shooting occurred during a routine check at the gas station, after an officer saw two men and approached them.
One of the men then pointed a handgun at the police officer, then shot at him multiple times, according to the statement.
"Fearing for his life, the Berkeley officer fired several shots, striking the subject, fatally wounding him," Schellman said.
The handgun was in the possession of the police, Schellman continued, adding that second man had fled the scene.
Protesters and commenters on social media were quick to question the police's version of events. At a news conference Wednesday morning, St. Louis County police released CCTV footage from the gas station, which they said corroborated the officer's account, claiming it showed the shot man raising a gun. However, the footage is of poor quality and the images are unclear.
Laura Hettiger, a reporter for St. Louis TV station KMOV, told the BBC, "As soon as I got there police started firing off flash bangs which are used to, hopefully, disperse some of the crowd.
"A lot of police are still on the scene," Hettiger said. "A couple of people have ended up looting the gas station just across the street."
Tuesday's shooting comes at a time of heightened tensions over police violence. The Garner and Brown cases have stirred public anger across the United States over racism within the security forces and the perceived impunity for officers involved in such incidents.
On Saturday, two New York police officers were shot dead in Brooklyn by a gunman who had posted on Instagram, "I'm putting wings on pigs today." The shooter, Ismaaiyl Brinsley, had reportedly also made references on social media to the Garner and Brown cases.
Follow Hannah Strange on Twitter: @hannahkstrange