Harrowing footage captured the moment a looter knocked out an elderly shop worker as he tried to defend his store amid the on-going Kenosha riots.

And in another incident, a pizza store employee was filmed elsewhere in the city pleading with rioters to stop, asking 'Are you trying to get Trump re-elected?'

Businesses and other institutions in the Wisconsin city have been left damaged and destroyed following three consecutive nights of rioting and looting spurred by the Sunday police shooting of unarmed black man, Jacob Blake, who has been left paralyzed.

On Monday night, an elderly worker of Sue and Keith's Magical Mattress Store, identified as Mr. Robert who is in his 70s, was filmed being callously knocked-out cold by one protester as he attempted to stop a fire in the store that was started by looters.

The following evening, on Tuesday, a worker at a Papa John's Pizza chain in the city center was seen remonstrating with protesters through a shattered window of the eatery, urging them to stop the vandalism because 'I've got kids to feed'.

In footage of the first of the two incidents, Robert is seen emerging from the smoke-filled store front in pursuit of a group of rioters with a fire extinguisher in his hand.

He begins blasting the extinguisher at the looters as they exit another entrance of the store, one of whom launches a glass bottle towards the elderly worker.