A pair of firebug ‘ninjas’ broke into a Newark apartment building and began setting fires inside a second-floor home, Newark police said.

The arsonists — wearing black ski masks and full ninja-style outfits — sauntered into the new Cherry Park Apartments on Sylvan Avenue through the front door around 8:30 p.m. on Sept. 3, police said.

They rode the elevator to the second floor, where they made their way to an empty apartment without forced entry and started setting fires, NBC News 4 reported.

The stealthy pyromaniacs were able to slip out through a side door.

Witnesses told the news outlet they saw flames coming from a window of the building, and then saw two people clad in black walking away from the area.

No one was reportedly injured.