A squatter suffered serious burns when the Glen Cove apartment he was staying in caught fire, causing him to crash through a second-story window to escape the flames, authorities said Saturday.

The unidentified man landed on the driveway of the Grove Street property, Glen Cove Fire Chief Joe Solomito said.

The victim was taken to a hospital and treated for second- and third-degree burns to his face, chest and arms, and smoke inhalation. Police said the injuries were not life-threatening.

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When firefighters responded to calls about a fire at about 11:30 p.m. Friday, no flames were visible outside. But when Glen Cove 1st Assistant Chief Philip Grella entered the building, he saw the fast-spreading fire, officials said. As Grella stepped back outside, Solomito said, "the back of the building lit up on him." Grella was not injured.

Moments later came the sound of shattering glass.

"All of a sudden, this guy comes diving out of the second-floor window," Solomito said.

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It's unclear how long the man had been staying at the property, which authorities characterized as abandoned and uninhabitable. Firefighters doused the blaze within an hour.

Det. Lt. John Nagle of the Glen Cove Police Department said a second squatter, who was in the building when the fire started, ran out and was unhurt.

Authorities are investigating whether the men started the fire to keep warm on a cold night. The county fire marshal's office said Saturday night that an official cause had not been determined.

The building, at 42 Grove St., housed two apartments, according to Nassau County tax records. A warehouse is also on the quarter-acre property, which sold in August, records show.

The property owner could not be reached Saturday.

With Robert Brodsky