A shark bit a Maui surfer Friday morning and severed his leg, authorities said.

The man, 61, was surfing off Waiehu Beach Park Friday morning in a surf spot known as Sand Piles when a shark bit him,” Maui County said in a news release. 

Police officers who arrived to the scene first tried to control the bleeding with tourniquets. His leg was “completely severed just below the knee,” officials said. 

Witnesses told CBS affiliate Hawaii News Now that other surfers helped the man swim back to shore.

“I heard this yell and I looked, and all of a sudden I just seen him splash, and I don’t know what was happening,” witness David Basques told Hawaii News Now. “…He swam himself back maybe more than half the way, and then I seen somebody jump in and they went bring him inside.”

The man was alert while being treated on shore and then taken to Maui Memorial Medical Center in critical condition.

“I would like to commend the patient for his strength and wherewithal, getting himself to shore,” Maui Fire Department Assistant Chief Jeff Giesea told reporters, according to KGMB. “I mean, that’s extraordinary. Whatever Good Samaritans offered assistance, I’d like to commend them as well.”

The incident prompted officials to close the beach park. Officials warned people to stay out of the water in the area. The public warning to stay out of the water for a mile in each direction of the incident will be in effect until at least noon Saturday. The warning will be extended if there is a shark sighting in the area.

Maui fire and ocean safety officials were patrolling the waters using rescue watercraft and a drone. State officials provided shark warning signs and helped with cordoning off the area.

There were no details provided on what kind of shark was involved.

In June, well-known surfer Tamayo Perry was killed in a shark attack while surfing off Oahu’s North Shore.