Two terrifying shark attacks happened at a North Carolina beach town within a little more than an hour on Sunday, leaving two teenagers severely injured, reported NBC News.

Both attacks happened in waist-deep water, about 20 yards offshore, authorities said Monday.

Witness Steve Bouser was on the Oak Island beach when a shark attacked a 12-year-old girl who was swimming. He told NBC News the incident was "like a scene out of 'Jaws.'" Someone carried the girl out of the ocean and a crowd rushed to help her, he said.

The girl, who was in shock, appeared disoriented. People asked, "Can you hear me?"

"She would respond not very enthusiastically, but you could tell she was still conscious," Bouser said.

Hospital officials report that the girl's left arm had to be amputated below the elbow. Her lower left leg has extensive tissue damage.

In the second attack also at Oak Island, a 16-year-old boy had to have his left arm amputated below the shoulder.

Though the injuries were initially described as life-threatening, authorities have reported that both victims had surgery and were in stable condition on Monday.

Authorities credited helpful bystanders with saving the two victims.

"Without them, we would have had a different outcome," said Brian Watts, the emergency services director for Brunswick County.

Oak Island Mayor Betty Wallace said the second attack "happened so quickly" that there was not enough time to alert swimmers.

"Our local police ATVs and the sheriff's boat and helicopter patrolled immediately after the second one, getting everyone out of the water," Wallace said.

Authorities have no plans to close the beach, according to NBC News, and added it was unclear whether one or two sharks were responsible.

The shark attacks happened near the Ocean Crest Fishing Pier, which is a popular destination for fishermen and beachgoers, Fox 8 reports. Fishing bait in the water could have attracted the shark.

George Burgess, director of the Florida Program for Shark Research at the University of Florida, told the Wilmington Star-News that mostly blacktip and spinner sharks measuring up to seven-feet long swim along the Carolina coasts.

He said that the sharks bite people in "mistaken identity situations," in which they mistake a human's splashing arms or legs as activity of their normal prey.

Four days earlier, on June 12, a 13-year-old girl survived what appeared to be a shark attack off the coast of Ocean Isle Beach, North Carolina.