The incident happened on New York Avenue and 2nd Street in Union City.
Around 5:30 a.m., fire officials had deemed the blaze contained but not under control. They were dousing the buildings with a tower ladder and from down below, and it appeared several of the buildings would be uninhabitable by the time the fire was extinguished, which was accomplished a few hours later. Hotspots lingered.
The fire was called in by a sheriff's officer who was patrolling a nearby park and saw flames shooting out of the ground-floor deli.
The main wood-frame building, with the deli and two floors of apartments on top, was completely gutted. Two attached residential buildings also suffered heavy damage, and two others attached to those were also scorched.
There are no injuries at this point, but officials say dozens of people were evacuated and may be permanently displaced.
"We're talking upwards of 25 to 30 people in all the buildings," North Hudson Regional Fire Director Jeff Welz said. "We don't have an exact count because some of them are in a shelter opened up by Union City. Obviously, the main building is going to be uninhabitable. And two adjacent buildings are probably going to be uninhabitable."
The scene remains active, with dozens of firefighters on the scene. Jersey City is offering mutual aid.