Riot police in the United States have been accused of shooting a photographer with a ‘non-lethal projectile’ as he was filming officers at the scene of an anti-Wall Street protest.

Scott Campbell, a participant in the protest, was videoing a line of police officers in Oakland, California during an Occupy demonstration last week.

Campbell, 30, told the San Jose Mercury News that he was shot in the thigh with a non-lethal projectile, possibly a rubber bullet, causing swelling and bruising.

?When I was approaching the line, an officer told me to stop and step back, so I stepped back five or ten feet and started filming, and I asked if that was OK,? he told the paper.

Shortly afterwards Campbell, who is thought to have been around 50 feet from police, is heard to cry out in pain as he appears to be hit.

The incident took place last Thursday at around 1am, shortly after other protesters had defaced a building and ?set fire to barricades?, according to the paper.

Campbell said he does ?social and digital media work?, and though he supported the protest he was not an active organiser.

The newspaper said police had yet to respond to its requests for comment.

To watch the video see HERE.