It's nightmare news that could make any parent think twice about letting their kids go in the water: a double shark attack on teens two miles apart on the very same North Carolina beach.

Sharks, possible bull or tiger sharks, attacked two teenagers less than two hours and two miles apart on the same stretch of sand in the popular resort town of Oak Island, North Carolina.

The first attack came at 4 p.m. when a 14-year-old started screaming and thrashing about in the water. A man swimming nearby grabbed her and got her to shore, said Mayor Betty Wallace, according to Reuters. The girl was airlifted to hospital and lost part of her arm. Her leg was also mauled.

Two miles east along, a 16-year-old boy was bitten as first responders tended to the girl. The teen lost his left arm, said the mayor.

Patrols raced up and down the shore telling beachgoers to stay our of the water.

Shark attacks are fairly rare, according to experts; they just get a lot of news coverage.

"I don't want everybody to think this is one of those areas where you really have to worry about shark bites," Wallace said. "But for the foreseeable future, people have to be extra vigilant."

Last Thursday, there was another attack 30 miles away in Ocean Isle Beach. ABC News reported; the victim, a 13-year-old girl, suffered cuts to her foot.

The twin attacks Sunday were even more unusual, one expert said.

“This is highly unusual – I have seen this twice in 40 years. Once in Egypt and once in the Florida Panhandle,” shark specialist  George Burgess of the University of Florida, told ABC.