Protests against the killings of black people by police were held in many cities across the US. Tensions between black citizens and police have risen palpably since the killings of Alton Sterling in Baton Rouge and Philando Castile in Minnesota by officers, and a retaliatory attack on police by sniper Micah Johnson in Dallas that killed five officers.

Black Lives Matter protesters arrested by police in Baton Rouge demonstrationIBTimes US

Many of the demonstrations focused on attempts to shut down major interstates. Police in riot gear managed to keep a group of protesters from blocking Interstate 110 in Baton Rouge. Scores of demonstrators were arrested after authorities warned that violence during the protests would not be tolerated. Baton Rouge police reported that at least 48 people were taken into custody after demonstrators clashed with police following a peaceful march to the state capitol.

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Sandra Sterling is comforted during community vigil in memory of her nephew, Alton Sterling, who was shot dead by police, at the Triple S Food Mart in Baton Rouge, LouisianaJeffrey Dubinsky
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Police officers wearing gas masks stand guard during a protest in Baton Rouge, LouisianaShannon Stapleton/Reuters
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Demonstrators raise their fists as law enforcement officers march down a street during protests in Baton Rouge, LouisianaShannon Stapleton/Reuters
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A tearful woman protests against the shooting death of Alton Sterling in Baton Rouge, LouisianaJonathan Bachman/Reuters
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A woman confronts armed police officers near the headquarters of the Baton Rouge Police Department, Louisiana,Jonathan Bachman/Reuters
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A woman cries near the headquarters of the Baton Rouge Police Department during a protest against the shooting death of Alton SterlingJonathan Bachman/Reuters
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A woman protesting against the shooting death of Alton Sterling is arrested by riot police officers near the headquarters of the Baton Rouge Police Department in LouisianaJonathan Bachman/Reuters
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Demonstrators gather after marching to the Louisiana Capitol to protest against the shooting of Alton Sterling in Baton RougeMark Wallheiser/Getty Images
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Demonstrators raise their fists after marching to the Louisiana Capitol in Baton RougeMark Wallheiser/Getty Images
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Protesters face off with Baton Rouge police in riot gear across the street from the police departmentMark Wallheiser/Getty Images
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Police officers start making arrests in Baton Rouge, LouisianaMark Wallheiser/Getty Images
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A demonstrator is arrested in Baton Rouge, LouisianaMark Wallheiser/Getty Images
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A man protesting against the killing of Alton Sterling is detained near the headquarters of the Baton Rouge Police Department in Louisiana

In St Paul, Minnesota, 21 officers were injured on Saturday (9 July) when they were pelted with rocks, bottles, construction material and fireworks. Hundreds of protesters had shut down I-94, a major thoroughfare linking the Twin Cities, snarling traffic. Police made arrests and used smoke bombs and tear gas to disperse the crowd.

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Police cars line up as protesters shut down highway I-94 in St Paul, MinnesotaStephen Maturen/Getty Images
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A police officer uses pepper spray as people gather on Interstate 94 in St Paul, Minnesota, to protest against the fatal shooting of Philando Castile by Minneapolis area policeAdam Bettcher/Reuters
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Black Lives Matter protesters are seen in clouds of tear gas in St Paul, MinnesotaStephen Maturen/Getty Images
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A police officer puts on his gas mask as protesters shut down I-94 in St Paul, MinnesotaStephen Maturen/Getty Images
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Bystanders watch as protesters and police face off in St Paul, MinnesotaStephen Maturen/Getty Images
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Police officers launch smoke bombs and tear gas canisters in St Paul, MinnesotaStephen Maturen/Getty Images
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People watch as the interstate is shut down by Black Lives Matter demonstrators in St Paul, MinnesotaStephen Maturen/Getty Images
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A sticker is placed on a fence pillar during a Black Lives Matter protest in front of the Governor's Mansion in St Paul, MinnesotaEric Miller/Reuters
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Protestors dance outside the Governor's Mansion in St Paul, MinnesotaStephen Maturen/Getty Images
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A protester wears a 'Cop Watch' vest outside the St Anthony Police Department in MinnesotaStephen Maturen/Getty Images
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A sign reading "Blue Lies Matter" lies on the ground outside the Police Department in St Anthony, MinnesotaStephen Maturen/Getty Images

Officials across the country grappled with a wave of demonstrations against excessive police force that has swept the country. Undeterred by heightened concerns about safety at protests after a lone gunman killed five police officers in Dallas, organisers went ahead with marches in New York City, Washington DC and other cities. Demonstrations spread outside the US: hundreds of people took part in a Black Lives Matter protest in London.

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A door with handles in the likeness of the Oakland Police badge is seen splashed with red paint in Oakland, CaliforniaStephen Lam/Reuters
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A woman with Black Lives Matter removes a sticker after a protest outside the Los Angeles Police Department (LAPD) headquartersPatrick T Fallon/Reuters
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People take part in a protest against police brutality and in support of Black Lives Matter during a march in New YorkEduardo Munoz/Reuters
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People walk over a chalk artwork featuring the names of people killed by police during a demonstration in support of Black Lives Matter in New YorkEduardo Munoz/Reuters
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A man and his daughter take part in a Black Lives Matter protest in New YorkEduardo Munoz/Reuters
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A demonstrator holds up a 'Black Lives Matter' sign in front of the White House in Washington, DCJoshua Roberts/Reuters
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Black Lives Matter demonstrators block the road outside the Houses of Parliament in LondonDaniel Leal-Olivas/AFP
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Demonstrators from the Black Lives Matter movement march through London during a demonstration against the killing of black men by police in the USDaniel Leal-Olivas/AFP

The most recent shooting deaths by police come after several years of contentious killings by law enforcement officers, including that of Michael Brown, a teenager whose death in the summer of 2014 caused riots and weeks of protests in the St. Louis suburb of Ferguson.