Multiple people have been treated for injuries at a Florida Airport after severe turbulence caused an A320 service to plunge over a kilometre in 60 seconds.

Two passengers and two flight attendants were injured when a plane plunged nearly 1600m during severe turbulence on Wednesday while flying from North Carolina to Florida, officials said.

Emergency services met Allegiant Flight 227 at St Petersburg Airport after it encountered a pocket of extreme turbulence on approach to landing.

The Allegiant service was travelling from Asheville Regional Airport to St. Pete-Clearwater International Airport, where it landed normally and taxied to the gate under its own power, the airline said in a statement. The plane was carrying 179 passengers and six crew members. BN9 News reported the incident happened around 20 minutes before it was scheduled to land.

The Airbus A320 dropped about 1524m, from an elevation of about 5.5km to 3962m, in less than two minutes, according to the flight-tracking website FlightAware.

Airport paramedics met the plane to assess the four injured people, Allegiant said. They were taken to a nearby hospital, but officials didn’t immediately provide details about their injuries.

Allegiant said it was working with the Federal Aviation Administration and the National Transportation Safety Board to investigate.

Passenger Lisa Spriggs and son Sterling were aboard the plane. Sharing photos with local news channel BN9, the paramedics boarded the plane to assess injuries before anyone was able to deplane.

Spriggs described a horrifying moment of weightlessness like something out of an action movie. “All of a sudden we hit major turbulence,” she told CBS News, witnessing a cabin crew member thrown off her feet. “Literally she flew up in the air like something in The Matrix, is the only way I can describe it.”

Earlier this month, a Hawaiian Airlines flight from Honolulu to Sydney hit severe turbulence, injuring seven people on board. And last year, 20 people were hospitalised, with 11 seriously injured, after turbulence struck a Hawaiian Airlines plane flying from Phoenix to Honolulu.

- Associated Press with additional reporting