A 13-year-old girl was the first to be a bitten off the crowded beach at Oak Island, North Carolina, on Sunday. Just an hour later a 16-year-old boy was attacked about two miles further along the beach.

Both victims were airlifted to New Hanover Regional Medical Center, in Wilmington, in a critical condition. Hospital spokeswoman Martha Harlan confirmed that both had lost an arm. The 13-year-old had her arm amputated at the elbow, and the 16-year-old had his removed below the shoulder. In addition, the girl suffered serious leg injuries.

Holidaymaker Steve Bouser told of the “nightmarish” scenes. “I saw someone carry this girl and people were swarming around and trying to help,” he said, quoted in The Guardian. “It was quite terrible.”

His wife, Brenda Bouser, said: “It was so much like a scene from Jaws.”

It is understood that holidaymakers attempted to stem the flow of blood from the girl’s injuries using a makeshift tourniquet, and that they kept talking to her in efforts to keep her conscious before emergency services arrived.

Red flags are being flown at most Brunswick beaches and a helicopter has been scouring the waters looking for the shark or sharks responsible. The nature of the injuries has led experts to suspect that the attacks may have been carried out by bull or tiger sharks.

Town manager Tim Holloman told ABC News: “Oak Island is still a safe place. We’re monitoring the situation. This is highly unsual.”

Shark Expert George Burgess, of the University of Florida, who publishes the International Shark Attack File, said: “This is the real deal threat. This is highly unusual – I have seen this twice in 40 years. Once in Egypt and once in the Florida Panhandle.”