Riot police and protesters clashed in the streets of Ferguson again, a day after the Missouri governor summoned the National Guard to help restore calm to the St Louis suburb where Michael Brown was fatally shot by a police officer.

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Police armed with a range of weaponry attempt to control demonstrators protesting the killing of teenager Michael BrownScott Olson / Getty Images
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A demonstrator wearing the stars and stripes takes part in a protest in Ferguson, MissouriJoe Raedle/Getty Images
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Demonstrators cover their faces as tear gas fills the airJoe Raedle/Getty Images
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Police officers arrest a demonstrator in FergusonJoe Raedle/Getty Images
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A demonstrator protesting the shooting death of Michael Brown wears a gas maskJoe Raedle/Getty Images
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An armed state trooper wearing a gas mask looks directly into the cameraScott Olson / Getty Images
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Demonstrators stand in the middle of West Florissant as they react to tear gas fired by policeLucas Jackson / Reuters
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A demonstrator raises his hands in front of a fog of tear gas hovering over West FlorissantLucas Jackson / Reuters
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A police officer raises his weapon at a car speeding in his general direction as a group of demonstrators stands on the pavementLucas Jackson / Reuters

Protesters filled the streets after nightfall, and officers deployed noisemakers and armoured vehicles to push demonstrators back. The officers also fired tear gas and flash grenades.

Crowd control remained the responsibility of police, with most of the National Guard units that had been summoned by Governor Jay Nixon keeping their distance from the protests and protecting a police staging area.

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Armed police are silhouetted against clouds of tear gas as they advance towards protesters in Ferguson, MissouriScott Olson / Getty Images
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Police officers react to the movements of a group of demonstratorsLucas Jackson / Reuters
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Police officers point their weapons at demonstrators protesting against the shooting death of Michael Brown in Ferguson, MissouriJoshua Lott/Reuters
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Police officers advance towards protestersJoe Raedle/Getty Images
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A protester dons a gas mask and covers his head with the stars and stripes on West FlorissantLucas Jackson / Reuters

After most of the streets had been cleared, authorities ordered reporters to leave, citing the risk from gunfire that had been reported.

Earlier in the day, Getty Images photographer Scott Olson was detained and bundled into a police vehicle while covering the protests.

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Getty Images photographer Scott Olson is placed into a paddy wagon after being arrested by police while covering the demonstrations in Ferguson, Missouri, following the shooting death of Michael BrownJoe Raedle/Getty Images
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Police lob tear gas at people walking near a protest over the killing of teenager Michael BrownScott Olson / Getty Images

The latest clashes came at the end of a day in which a pathologist hired by the Brown family said the unarmed 18-year-old suffered a bullet wound to his right arm that may indicate his hands were up or his back was turned.

An independent autopsy determined that Michael Brown was shot at least six times, including twice in the head, the family's lawyers and hired pathologists said.

Witnesses have said Brown's hands were above his head when he was repeatedly shot by an officer on 9 August in Ferguson.

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Brown family attorney Daryl Parks displays an autopsy diagram and points out a head wound that was likely fatal to Michael Brown during a news conference in Ferguson, MissouriReuters
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A demonstrator holds a copy of Blacks Law Dictionary during a peaceful march down West FlorissantLucas Jackson / Reuters
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A demonstrator holds a sign calling for the arrest of Darren Wilson, the police officer who shot Michael Brown in Ferguson, MissouriJoshua Lott/Reuters