The Victoria Police Department is conducting a use-of-force investigation after a video surfaced online showing police officers violently arresting a number of men outside a downtown nightclub.

The footage, taken at around 12:30 a.m. on March 21, shows two officers push a man to the ground before one of them sends a swooping kick to his torso.

"Ow, ow, ow," the man yells, clutching his stomach.

The cop then repeatedly digs his knee into the man's back and swears at him as he and another officer put him in handcuffs.

Sgt. Grant Hamilton told the officers witnessed six people, in various states of intoxication, assaulting a man outside the Social Club on Store Street.

"There was a victim that you see in the video lying on the street," Hamilton said. "What you see is the officers trying to arrest everybody involved in that assault."

All six men were arrested, questioned, and released less than an hour later, Hamilton said. The victim was taken to hospital and treated for head injuries.

The Victoria Police Department Professional Standards Section has launched an internal investigation into the incident, and the Office of the Police Complains Commissioner has been notified.

"They will look at the circumstances and the context in which the use of force was applied and determine whether it was justified," Hamilton said.

None of the men arrested have filed complaints.

"The complaints we have received have been from people who have viewed the video," Hamilton said.