A shark has bitten a 68-year-old man several times off North Carolina, officials said, the seventh attack in the US state's coastal waters in less than three weeks.
The man suffered wounds to his ribcage, lower leg, hip and hands as he tried to fight off the animal at a beach on Ocracoke Island, said Justin Gibbs, a local emergency official.
"The individual was actually located right in front of the lifeguard tower when it occurred," said Mr Gibbs, who added that witnesses reported the animal was about 7ft long. "He was pulled under by the shark. He was bit several times."
The victim was swimming in waist-deep water with his adult son about 30ft offshore, the National Park Service said. There were no other swimmers injured.
Seven attacks along the North Carolina coast in the space of three weeks makes it the most in at least 15 years. Most were attacked in similarly shallow water.
Experts say the recent spate of attacks along the coast of the Carolinas is due to so many more people getting in the water. Americans made 2.2 billion visits to beaches in 2010, up from 2 billion in 2001, according to a US Army Corps of Engineers estimate.
Scientists say there have also been reports of small bait fish coming closer to shore this year, which attracts sharks. There have also been reports of larger numbers of sea turtles along the coast, which sharks also like to eat.
Holidaymaker Laura Irish Hefty said she was about 100 yards away when she saw a crowd gathering on the beach and went to investigate. She said her husband saw blood on both the man's legs. The man was treated on the beach for about 20 minutes, according to Ms Hefty, and then an emergency helicopter flew him to a local hospital.
Swimmers were back in the water at that spot within a couple of hours of the attack, she added. "Nobody seems to be that scared," she said.
Meanwhile, a 32-year-old surfer was critically injured by a shark in another attack in Australia, at the same coastal town where a Japanese tourist was killed in February.
A police statement said the local man was surfing with two friends at Light House Beach in Ballina when he was bitten by a shark, "suffering significant injuries to his lower legs".
His friends helped him to shore and he is believed to have been flown by helicopter 60 miles north to Gold Coast Hospital.
Police have released no details about the shark.
A 41-year-old Japanese tourist was surfing just north of Light House Beach at Shelly Beach in February when a great white shark 10ft to 13ft long tore off both his legs.