Three men and some security guards were filmed clashing at the intersection of Moseley and Elizabeth Streets in Glenelg.

Onlookers appeared to step in to try to break up the violence about 7.50pm.

”Let him go, let him go!” one person could be heard saying in the clip.

A person can be seen lying on the ground with bystanders helping him into the recovery position.

The fight continued for more than two minutes, even as men fell to the ground, multiple blows landing square on unprotected heads.

The chaos finally came to an end as police arrived.

Four others were taken to hospital and treated for non-life threatening injuries.

The security guards work at the Colley Hotel. The bar told 9News the altercation was sparked by an unprovoked attack outside the venue.

Just hours earlier SA Police had announced measures to stamp out anti-social behaviour by making Glenelg a “declared public precinct”, giving police more power to search and even ban troublemakers.

Local workers are already eager to see the extra powers deter similar incidents.

“That was the worst one I’ve seen. Usually, it’s just people yelling,” local cafe worker Victoria Zanotto said.

Three men in their 20s were charged with assault and affray. Additionally, one of them, a 28-year-old from Morphett Vale, was also charged with property damage.

They were granted bail to appear in Adelaide Magistrates Court next month.

Four others were taken to hospital and treated for non-life threatening injuries.