Young boy lands sickening punch on man in Perth

Two 13-year-old boys are under investigation over a brutal late night attack in the heart of Perth that was caught on camera.

The attack happened on William Street around 11pm yesterday.

In the video, the boys appear to overpower the victim, knocking a drink from his hand.

The victim tries to fight back but is then brutally punched and knocked to the ground.

By this morning, video of the attack had been shared thousands of times online, sparking outrage and death-threats to the boys and their families.

9NEWS has spoken to the mother of one of the boys involved. She says her son is remorseful and knows the extent of the trouble he's caused, she also claims he is being punished.

Police are investigating and have launched a public appeal for the victim to come forward.

Since July, there have been 172 assaults in Perth city.