An unidentified swimmer was attacked and killed by a shark off a beach in Sydney, Australia. The incident was the first reported fatal shark attack in Sydney since 1963.

Officials said human remains of the swimmer were located Wednesday, seemingly with "catastrophic injuries." A video of the incident was uploaded on social media. The video graphically showed how the swimmer was attacked off a crowded beach by what witnesses said was a 14-foot great white shark.

Police responded to emergency calls and arrived at Buchan Point in Sydney's Malabar, where they discovered half of the swimmer's body still with a wetsuit on. Emergency services later arrived, but paramedics said there was nothing they could do.

One witness said he saw the swimmer being "mauled" by a large shark and the waters around him turning red. Another witness who was fishing nearby said the swimmer, who was wearing a wetsuit, was dragged under the water. He added that he felt helpless as the swimmer was attacked, and he couldn't stop shaking and vomiting at the horrific scene.

After the incident occurred, people were still swimming off the same beach. Most were reportedly unaware that an attack had happened. Officers arrived to close down Little Bay Beach as they continued to search for the swimmer's remains.

The MP for the state electorate of Maroubra, Michael Daley, arrived at the scene and told reporters that he was shocked at what had happened. He added that he immediately traveled to the beach once he heard about the attack.

The Department of Primary Industries (DPI) and local police said they would be closing down the beach for the next 24 hours. Nearby beaches such as Malabar, Maroubra, Coogee, Clovelly, and La Perouse were also closed down.

The public has been told to stay away from the beach. Two helicopters, a boat, and three jet skis were dispatched to the scene of the incident and the surrounding area to look for any signs of the swimmer's body and the shark. It remains to be seen if other beaches south of Little Bay Beach would also be closed down.

The last fatal shark attack in Sydney was reported in 1963. Before that, there was a man killed in Sydney Harbor in 1955. Both were, reportedly, killed by a bull shark. Nationally, the last reported fatal shark attacks happened in Western Australia in November last year. Three swimmers were killed by sharks in separate incidents last year.

Shark attacks in Sydney are rare as there is a network of shark nets surrounding Newcastle north of Sydney to Wollongong south of the NSW capital. The DPI said the nets are not designed to completely prevent sharks from entering beaches but are instead designed to deter them from establishing hunting territories.