NEW YORK (CBSNewYork) — Several families are out of their apartments after a five-alarm fire tore through a building in the Bronx.

The fire broke out around 6:45 a.m. Wednesday on the sixth floor of a 100-unit apartment building at 1920 Walton Ave. in the Tremont section.

Residents said they felt the heat, smelled the smoke and some were woken up by knocks on their doors as neighbors urged them to get out, CBS2’s Janelle Burrell reported.

“I was in like a deep sleep. I just jumped up, my heart was pounding, I didn’t understand what was going on. I just jumped up in fear,” said resident Raquel Ruiz, who grabbed her dog and ran outside where she joined hundreds of her neighbors.

“We saw the fire coming out the sixth floor. I was panic,” resident Mamady Traore said.

Video of the scene showed a plume of thick smoke billowing from the top floor.

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The intensity of the smoke and heat sent firefighters to the hospital and emergency responders tended to residents on the scene.

“A lot a lot of smoke,” resident Jairo Qezada said. “I had to run out without shoes.”

About 200 firefighters responded to the blaze which was brought under control around 8:30 a.m.

Neighboring buildings were evacuated as a precaution.

The fire marshal is still working to determine what ignited the flames, but investigators say the fire began in the space between the building’s roof and the sixth floor.

“That’s an area in this type of building where fire spreads rather quickly, it did in this case. Multiple hand lines were used firefighters did a very aggressive interior attack to save this building,” Fire Commissioner Daniel Nigro said.

Eight firefighters and four civilians suffered minor injuries.

The Red Cross is assisting displaced residents.