A surfer has been killed by a shark off the east coast of Australia. The man, believed to be in his 50s, suffered "critical injuries to his upper right thigh," police said.

According to the New South Wales police, onlookers pulled the man from the water but died shortly after.

In a tweet, a representative for NSW Ambulance confirmed medics arrived to treat the victim and apply CPR. "Despite the best efforts of paramedics and bystanders at the scene the man could not be resuscitated," the NSW Ambulance said on Twitter.

The incident Tuesday is the first deadly shark attack this year in Australia. Last year, sharks killed eight people, CBS News said.

Immediately after the incident, Forster Main Beach and Tuncurry Beach were closed so the Department of Primary Industries can determine the species responsible.

Witnesses said the man was on vacation at Tuncurry Beach and surfing with friends before the attack. Superintendent Christopher Schilt said the man spotted the shark before the attack and attempted to alert other surfers.

Brian Wilcox, president of Lower North Coast Surf Life Saving branch, said a drone search following the incident spotted two sharks.

"It's pretty unprecedented. I can't recall ever having a shark attack in this area," Australian Broadcasting Corp. quoted Wilcox as saying.

At this time, scientists at DPI believe the bite may have been caused by a 4-and-a-half-meter white shark based on an analysis of photographs of the bite, ABC reported.