A 17-year-old boy is the third victim of a shark attack within one month, in the central coastal province of Binh Dinh.
Huynh Nhu Hoang said he was swimming at Quy Nhon Beach on Tuesday afternoon when he spotted a shark over one meter long.
Hoang then tried to swim to shore, but the fish bit his left foot when he was some three to four meters from the beach, he said.
Doctor Nguyen Xuan Dung from Military Hospital No.13, where the victim was hospitalized, said the bite was six centimeters wide and 12 centimeters long.
On May 19, two women were attacked by an unidentified fish, believed to be a shark, when swimming at the same beach.
At least ten people have been attacked by unidentified fish. The first attack was reported last July.
Since then, local fishermen have caught three sharks. The latest one, weighing 60 kilograms, was caught last month and was believed to be the culprit.
In March, Binh Dinh fishermen caught a shark weighing more than half a ton, just one month after a one-ton great white shark was caught near the shore of neighboring Phu Yen Province.