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(Reuters) - A transformer fire ignited by a lightning strike plunged much of the city of Fort Lauderdale, Florida, into darkness on Tuesday night, police and utility officials said, but there were no immediate reports of injuries.

The blaze, which lit up the night sky with raging balls of flame several stories high, engulfed one of three transformers housed at the stricken electrical substation in the city, Florida Power & Light (FPL) spokesman Bill Orlove said.

A number of witnesses quoted in local media accounts said they heard multiple explosions at about the time the blaze erupted.

The fire and resulting blackout came as Fort Lauderdale played host to throngs of visiting college students converging on the city and neighboring South Florida communities this month for spring break festivities, an annual beer-soaked rite of youthful revelry.

Nearly 32,000 Broward County homes and businesses were without electricity shortly after the fire erupted, according to a “Powertracker” map posted on the website of the utility, a subsidiary of NextEra Energy, Inc..

Company spokesman Chris McGrath said the outage initially left about 22,000 Fort Lauderdale customers without electricity - nearly a fifth of FPL’s service base in the city north of Miami.

“We are aware of a service interruption and a fire at a substation in Fort Lauderdale,” McGrath said. “Crews are on site working to restore power safely and as quickly as possible.”

The number of Broward County customers without electricity fell to about 21,300 within an hour of the first reports of the blackout, and Orlove said all but about 7,500 had power restored about an hour later.

Orlove said the cause of the fire was under investigation, but Fort Lauderdale police said on Twitter that the power outage was caused by a lightning strike on the FPL substation.