Protesters in Berkeley, California hurled objects at police, who responded by firing tear gas during another night of demonstrations over the death of a black man who was put in a chokehold by a police officer in New York.

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Police officers use batons as they clash with people protesting against police violence in BerkeleyStephen Lam/Getty Images
berkeley police violence protest
A protester flees as riot police officers with batons try to disperse a crowd comprised largely of student demonstratorsNoah Berger/Reuters

A crowd of about 750 demonstrators swarmed freeway overpasses at two locations in the university town near San Francisco.

Protesters smashed windows and threw rocks and bricks at police, who responded with tear gas. Berkeley police didn't say if any protesters were hurt.

The California Highway Patrol's Golden Gate division said on its Twitter feed that gas was fired after some demonstrators began hurling objects it described as unspecified "explosives". The Oakland Tribune reported that police fired rubber bullets.

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Police officers deploy teargas while trying to disperse a crowd comprised largely of student protestersNoah Berger/Reuters
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People retreat as police officers deploy tear gas to disperse student protesters in Berkeley, CaliforniaNoah Berger/Reuters
berkeley police violence protest
A woman is helped to recover from tear gas exposure during a protest against police violence in BerkeleyNoah Berger/Reuters
berkeley police violence protest
A police officer in riot gear with a broken visor stands on Telegraph Avenue in Berkeley during a protest against police violence and militarisationStephen Lam/Getty Images

On Saturday (6 December) evening, what had begun as a peaceful march ended in an extended confrontation between demonstrators and police, resulting in six arrests, damage to local businesses and minor injuries to three police officers.

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An officer stands near a police van vandalised by protesters in Berkeley, CaliforniaNoah Berger/Reuters
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A police officer raises a weapon during an attempt to control protesters in BerkeleyStephen Lam/Getty Images
berkeley police violence protest
A demonstrator throws a tear gas canister back towards the police lineStephen Lam/Getty Images
berkeley police violence protest
Police officers board an armoured vehicle on the fourth night of demonstrations in BerkeleyStephen Lam/Getty Images
berkeley police violence protest
A protester gestures at a line of police officers during a protest against police violence in Berkeley, CaliforniaNoah Berger/Reuters
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A man is detained by police during a demonstration in Berkeley, CaliforniaStephen Lam/Getty Images

New York was quieter over the weekend. Few protesters were out on Saturday night, when a cold, steady rain fell in the city.

The killings of Eric Garner in New York and Michael Brown, an unarmed black teen, in Ferguson, Missouri, have highlighted the strained relations between police and African-Americans and rekindled a national debate over US race relations.

In both cases, grand juries decided not to charge the white police officers involved, leading to days of protests in major cities.

The deaths led to "two of the worst weeks" in modern American history, Philadelphia Mayor Michael Nutter, a black man himself, told NBC on Sunday.