A massive three-alarm fire caused the partial collapse of a three-story building as New Jersey firefighters battled to contain the blaze early Monday.

The fire broke out just before 1 a.m. on the second floor of a Paterson commercial and residential building, NJ.com reports. Crews were still at the scene of the blaze as of 8 a.m., which had between 65 and 70 firefighters responding.

No injuries from the fire were reported, but four people were displaced by it. 

"We've established a collapse zone and firefighters are not allowed to enter the collapse zone for any reason. Their safety is paramount right now," Paterson Fire Chief Brian McDermott told WABC-TV. "The building is a total loss. It's gutted, it's collapsing as we speak."

The cause of the fire is under investigation.