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As protests against police brutality and institutional racism flared up across the United States on Friday, many turned contentious. Protesters in major cities set fire to police cars and damaged buildings while several incidents in which police officers appeared to escalate violence were captured on social media.

In Brooklyn, the passenger door of a police car driving by protesters was flung open, hitting one of the demonstrators, and another officer was filmed throwing a female protester to the ground. She ultimately wound up in the hospital.

But it wasn't just protesters who were targeted by some members of the police. Hours after a CNN news crew was arrested while covering protests in Minneapolis, a Louisville police officer fired pepper balls at a local television news crew reporting on demonstrations in the Kentucky city, much to everyone's confusion.

Elsewhere, a 19-year-old man was shot and killed in Detroit by an unknown suspect. It's unclear if the victim was a protester, but the shooting occurred where Detroit's demonstration was taking place.

As violence escalates, governors like Georgia's Brian Kemp (R) and Minnesota's Tim Walz (D) have called in the National Guard, and the Pentagon reportedly has military police on standby.