A witness told NBC News on Monday that it was "like a scene out of 'Jaws'" when a shark attacked a girl swimming in waist-deep water off the North Carolina coast — one of two attacks in quick succession that cost children their arms.

Steve Bouser was on the beach at Oak Island when a shark attacked a 12-year-old girl. He described watching someone carry the girl out of the ocean, then a crowd rushing to help her. One woman yelled for people to make a tourniquet.

"Everybody was screaming, 'Get out of the water!'" he said.

The girl was "obviously going into shock," he said. He recalled people asking, "Can you hear me?" "She would respond not very enthusiastically, but you could tell she was still conscious," he said.

Hospital officials said the girl's left arm was amputated below the elbow and her lower left leg had tissue damage. In the other attack, also at Oak Island, a 16-year-old boy's left arm was severed below the shoulder.

The attacks happened less than an hour and a half apart. Both victims were in waist-deep water, about 20 yards offshore, authorities said Monday.

Dispatch recordings from 911 captured the horror: "It looks like her entire hand is gone," a woman said after the shark attacked the girl. After the attack on the boy, a caller said: "It bit a man's arm off!"
The injuries were described as life-threatening, but authorities said both victims were out of surgery and in stable condition on Monday at a hospital in Wilmington. The boy's condition was upgraded to good.

The girl's family has asked that her name and condition not be released.

Authorities announced no plans to close the beach.

They said it was still unclear whether one or two sharks were responsible.

Authorities credited bystanders with helping save two lives. "Without them, we would have had a different outcome," said Brian Watts, the emergency services director for Brunswick County.

The boy was visiting the beach from Colorado Springs, Colorado. Authorities did not release his name, but the hospital released a statement from his mother in which she thanked "the people who saved him through their quick actions on the beach," emergency workers and hospital staff.

"He's in good shape," said Dr. Borden Hooks III, who performed surgeries on both patients at New Hanover Regional Medical Center. "To some degree, he's awake and talking to us. He and his family will have to deal with this together."

Daniel Abel, a marine biologist at Coastal Carolina University in South Carolina and a shark expert, said the same shark probably attacked both swimmers.

"The probability that it's two different sharks is vanishingly low," he told NBC News by phone. "But, you know, I could be wrong. These are solitary animals. They are not schooling together. It could be one animal that was in the same place people were."