A shark attacked and killed a swimmer off a Sydney beach causing "catastrophic injuries", police and ambulance services said.
There were dozens of other people in the water at the time of the deadly attack with horrified witnesses 'left vomiting' as the predator struck.
Local media said it was the first fatal shark attack in Sydney since 1963.
Emergency services were called at around 4.35pm to Buchan Point, Malabar, in Sydney's east, NSW police said. It said the Little Bay Beach has been closed.
"Officers attached to Eastern Beaches Police Area Command, with assistance from the Marine Area Command and Surf Life Saving NSW, attended and located human remains in the water," it said.
The police have so far offered no information about the identity of the swimmer.
A NSW Ambulance spokeswoman said paramedics were called to Little Bay, "unfortunately this patient had suffered catastrophic injuries and there was nothing paramedics could do.
A witness described how he was fishing close by when he saw a man wearing a wetsuit swimming across the bay.
He said the swimmer was suddenly dragged under the water by a "large" shark.
"When he went down there were so many splashes," the man told ABC news.
"It was terrible. I am shaking. I keep vomiting. It's very, very upsetting.
"He just went down for a swim, enjoying the day, but that shark took his life."
Another fisherman, Kris Linto, told Nine News: "Some guy was swimming and a shark came and attacked him vertically."
A horrifying video shows dozens of fishermen and other beachgoers reacting after seeing the disturbing attack.
One could be heard shouting: "Someone just got eaten by a shark. Oh man! Oh no! That's insane. That's a great white shark,' one fisherman can be heard yelling in footage.
"I just saw a four to five metre great white explode on the surface right here on a swimmer and it was like a car landing in the water.
"F*** man, I heard a scream and the shark was just chomping on his body and the body was in half here just off the rocks.
"It came back and swallowed parts of his body and that was it."
