IHOP says, “no mask, no service,” according to TMZ.

According to reports, one patron did not like this and “went to town on the staff with a knife.”

A 40-year-old female employee got her arm cut by the man.

The suspects have not yet been apprehended.

More from TMZ:

Law enforcement sources tell TMZ … this wild incident went down Tuesday in Queens where surveillance video captured the horrifying scene. At first, you see the customer in the waiting area with another guy — although, we’re told there were at least 3 men who rolled in together.

The video shows the guy who allegedly refused to put on a mask storm back into the IHOP and charge past a table and other waiting customers … apparently trying to get at someone off-camera.

While trying to get a hold of that person, the guy reaches over and grabs something from his friend — cops say it was a knife — and then chases some workers through the restaurant. Toward the end of the video, he actually swings at someone before booking it.