A nightmare unfolded for an employee at a Florida naval base on Monday when a shark interrupted his snorkeling break, prompting chilling screams that were captured on video. 

The civilian employee at the Naval Warfare Center in Panama City was swimming just off the shore at 11.45am on Monday when he was attacked by a shark, according to Naval Support Activity. 

An onlooker captured the attack, which showed the victim screaming 'help' as he thrashed in the water. While he attempted to escape the aquatic beast, a fin emerged from the water. 

Commander Tristan Oliveria told NBC News that the employee was snorkeling during his lunch break when the attack transpired. 

The victim has not been identified. The Naval station said the employee's arms were severely injured, but he was eventually rescued by onlookers. 

There were no other injuries reported. The employee was transported to a local hospital in critical condition. 

A 911 call from the incident revealed a concerned witness reporting the attack, telling the operator that the victim's arm was 'there, but it's not,' when asked if limbs were severed.

The video of the chilling attack went viral on social media, with one user commenting, 'My worst nightmare comes true. Just like the opener in Jaws. That is horrific. How his Life has forever changed in an instant. Praying for this young man.' 

'Prayers for a full recovery. Scary way to spend a lunch break,' another wrote. 

'That's one brutal lunch break. One swim. One bite. Life changes right there,' a third added. 

The terrifying attack is the second in the Florida panhandle within the last week. The incident occurred just a few days after a bull shark bit a fisherman, the Pensacola News Journal reported. 

Lifeguards and emergency responders arrived on scene of the bull shark bite and the fisherman was airlifted to a local hospital with non-life-threatening injuries. 

'He hooked a bull shark, and he landed on the beach and tried to take the hook out and got bit on the upper leg,' Escambia County Water Safety Chief Dave Greenwood told the outlet. 

Despite the back-to-back attacks, experts have cautioned that shark attacks are unlikely. 

Dr John Carlson, a research biologist with the National Oceanic and Atmospheric Administration, told local CBS affiliate, WJHG, that sharks migrate into coastal areas like the Florida Panhandle to give birth during this time of year. 

'The reality is, the likelihood is very low, you're more likely to be injured by your lawnmower, you're more likely to be injured by getting bit by a dog, there's more likelihood of you being hit by a television set than you being attacked by a shark,' he added when asked about the attacks. 

Carlson warned swimmers to avoid cloudy water and swimming at dawn or dusk, as it's easier for sharks to mistake humans for prey. 

The Daily Mail has reached out to the Naval Warfare Center for an update on the recent attack.