Two hundred firefighters were battling a massive blaze on the top floor of a Harlem apartment building Friday, fire officials said.

The raging five-alarm inferno, which broke out around 3:15 p.m., sent thick black smoke billowing in the air from the six-story building at 144th Street and Broadway in Hamilton Heights.

Fiery debris reportedly fell to the ground as the roof caved in — but no injuries have been reported thus far, according to fire officials.

No one is currently inside the building, the FDNY said.

Television footage shows the entire top of the building engulfed in flames.

“There’s a major fire on west side of Manhattan right now,” wrote @jmullaly, sharing a video of the blaze from Fort Lee, NJ.