Lifeguards closed off a two-mile stretch of ocean in Hawaii after a woman was injured in an apparent shark attack.

Officials say the woman was snorkeling about 50 yards off Makaha when she was injured Friday. She has been taken to The Queen's Medical Center in serious condition with a wound to her upper extremities.

Paramedics say the woman made it to shore on her own and was aided by bystanders.

Lifeguards have cleared the ocean for a mile in each direction along the Waianae Coast and posted shark warning signs.

A police helicopter reported seeing a large shark near the shoreline just after the woman was hurt.