Surfer's leg 'severed at knee' in Hawaii shark attack

A man's leg has been severed below the knee after he was attacked by a shark while surfing in Hawaii.

The 61-year-old man was surfing off Waiehu Beach Park on the island of Maui on Friday morning when a shark bit him.

Police officers who arrived at the scene first tried to control the bleeding with tourniquets.

His right leg was "completely severed just below the knee", Maui County said in a statement.

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

The man said he did not see the shark approach, authorities reported.

The incident prompted officials to close the beach park.

Officials warned people to stay out of the water 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, pro surfer Tamayo Perry was killed in a shark attack while surfing off Oahu's North Shore.