Image copyright Chris Kleponis Image caption PC Michael Evers is seen before an alleged car-drive at Chris Kleponis
A car drove through a crowd protesting against the Dakota Access pipeline at the Minneapolis city council chambers.
Four people were injured, including the pipeline’s engineer, Chris Kleponis, who was taken to hospital after being hit by broken glass.
The protesters were demanding that the council refuse permission for construction of the disputed oil pipeline.
In the following images, he and other protesters are seen shouting and running as a silver car is seen accelerating towards them.
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Chris Kleponis. Picture via Twitter/ @CCAdhoc
Image copyright Chris Kleponis Image caption Chris Kleponis was hit by broken glass while running for cover
Image copyright Chris Kleponis Image caption Photographs of the scene
Image copyright Chris Kleponis Image caption The car appears to be coming from North Minneapolis
Image copyright Chris Kleponis Image caption Protesters scream as the car drives past
Image copyright Chris Kleponis Image caption A person attempts to move the car
Image copyright Chris Kleponis Image caption Protesters are seen running
Image copyright Chris Kleponis Image caption Chris Kleponis was hit by broken glass
People taken away from the scene have included University of Minnesota students and City Council member Jacob Frey, who was injured after jumping off a balcony.
Dr Amber Howell, the woman whose photograph first alerted the media, said she heard the car approaching from the southwest towards the second floor at about 20.30 local time (23.30 GMT).
“I just heard screeching tyres and people going flying,” she told Reuters.
The four protesters arrested include two local residents and one from Indiana, the Minneapolis Star Tribune reported.
The group had been protesting since Tuesday about plans to dig under Lake Oahe, which is part of the Missouri river.
Image copyright Zack Brown Image caption Protesters were shouting slogans against the Dakota Access pipeline before the incident
Image copyright Zack Brown Image caption Zack Brown said the car drove close to where he was standing
The protesters had been holding vigils outside the council chambers since Tuesday to demand that a council member and the mayor not issue permits for the project.
Dozens of them, wearing so-called “free-water jugs” made from toilet-roll holders and jugs, were able to squeeze past police and have what appeared to be a press conference at the mayor’s office, only for police to throw them out at the door.
Dakota Access Pipeline spokesman Craig Stevens denied the video of the incident was authentic.
He told the Press Box of the Star Tribune: “I can’t tell you how I know it’s not the real thing because they’ve made the same mistakes before and I’m sure it’s the same stunts.”