NEW YORK (CBSNewYork) — The FDNY says two people were seriously injured after jumping out of a burning building in Manhattan early Wednesday morning.

The two-alarm fire broke out in a four-story apartment building just before 4 a.m. on 147th Street and Amsterdam in Hamilton Heights.

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1010 WINS’ Steve Sandberg reports residents believe the fire was deliberately set

FDNY Chief Raymond Stanton told CBS 2’s Jay Dow that it appears the fire started on the second floor and spread so fast that a 52-year-old man and 23-year-old woman had to jump out of the back window in order to escape the flames.

1010 WINS’ Steve Sandberg reports both the man and woman broke their legs and were transported to a local hospital.

One man told Sandberg the smell of smoke woke him up and he immediately went to the door of his third-floor apartment and quickly realized he was trapped.

“I got burned from opening the door, the smoke was coming so heavy so I had to go through the window,” the man said.

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He shimmied his way across the building’s brick facade to the neighboring brownstone.

Dow reports four firefighters were also injured.

No word yet on how the fire started.

Stanton said the fire appears to be suspicious because of how heavy the flames were on the second floor.

Sandberg reports the building was the scene of a fire last month.

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Firefighters were able to knock out the fire in about 45 minutes and prevented the blaze from spreading to adjacent buildings.