WARNING GRAPHIC CONTENT: Police are investigating a disturbing alleged attack after a video appearing to show an MMA fighter mercilessly beating a juvenile was shared thousands of times on social media.

The video appears to show a man, identified by social media users as an American fighter named Tony Cojocaru, callously punch and slap a younger man in the face, head and abdomen dozens of times until he is left cowering in a foetal position on the ground.

View photos A video appearing to show a man identified as American fighter Tony Cojocaru callously beat a juvenile until he cowers on the ground. Photo: Facebook/Kevin D Wise More

View photos The man identified online as MMA fighter Tony Cojocaru. Photo: Facebook More

The harrowing clip shows a young man, who police have identified as a juvenile, recoiling on a couch as the attacker points and asks menacingly:

"Do you think I'm playing with you, bro?"

He violently punches the young man in the head, who tries to shield himself with his arms.

View photos Photo: Facebook/Kevin D Wise More

A male voice from behind the camera can be heard saying "Tony, Tony," as the attacker continues to assault the young man.

"Shut the f--- up or I'll kill you," the attacker responds, pointing to the person behind the camera while grabbing onto the young man's hair.

"Don't f---ing move, don't move," he says, punching and kicking the victim.

View photos Photo: Facebook/Kevin D Wise More

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