(AP) -- A Florida-bound plane at LaGuardia Airport was evacuated after its crew reported heavy smoke emanating from the aircraft.

But a spokeswoman for the Port Authority of New York and New Jersey, which operates the airport, says firefighters didn't find any smoke when they responded to the Spirit Airlines plane Saturday morning.

Airline spokesman Stephen Schuler says there were reports of sparks in the power unit that provides electricity to the Airbus 321 when it's grounded.

He says the unit automatically turned itself off after detecting an issue.

Port Authority spokeswoman Cheryl Albiez says 228 passengers and seven crew members were then taken off the Fort Lauderdale-bound flight.

There were no reported injuries.