THIS is the unbelievable moment a shark chased a teen as he was hauled out of the water following an attack that left his arm hanging off by sinew.

Emergency services were called to reports of the attack at Cabarita Beach on New South Wales‘ north coast, Australia just before 4pm on Sunday.

A massive shark, believed to be a bull shark, attacked a 16-year-old, severely injuring his right leg, hand, and arm, according to reports.

Astonishing video shows other surfers and swimmers rushing to rescue the teenager, while the shark’s large fin could be seen ominously behind him.

Screams could be heard in the background as a brave person punched the shark while others scrambled to safety.

But rescuers continued to be stalked by the creature as they carried the injured boy to safety.

One shocked onlooker exclaimed in the clip: “Oh my God, that’s the shark.”

And another said: “Oh f***! That’s really scary!”

Thankfully an off-duty paramedic was at the scene and helped the teen using a tourniquet to help stop the excessive bleeding.

One of the heroes who raced to help the boy after hearing his deafening screams was Brazilian Thiago Collel.

Recalling the horror incident, he explained how the boy sustained injuries that left one of his arms hanging off by a thread of sinew.

A 39-year-old witness told the Daily Mail: “When I reached the shore, he had already been pulled out of the water by a group that included an off-duty paramedic who happened to be on the beach at that moment.”

“His bicep was destroyed – you could see all the muscle, flesh and bone.

“He lost a scary amount of blood. I was covered in it.”

The group then carried the boy out to safety on a surfboard they used as a makeshift stretcher.

Collel said he and several others “were just trying to keep him calm, holding his head and making sure he was okay”.

He added: “I just kept talking to him and he told me how he fought off the shark by kicking and punching it away.”

The boy was then airlifted to Gold Coast University Hospital by the Westpac Rescue Helicopter.

He remains here in serious but stable condition, the news site added.

A second chopper was deployed to track down the shark after the horror incident, but to no avail.

The species of shark currently remains unknown, but locals believe it was a bull shark.

Some even fear it could be a two-metre great white.