A man stabbed a security guard at the Apple Store in Chelsea during a dispute over wearing a mask inside the company on Friday night, police and law enforcement sources said.

A quarrel broke out in the store on West 14th Street and Ninth Avenue around 6:30 p.m., after the 37-year-old guard asked the customer to put on a mask, according to sources.

The guard sustained head and arm injuries and was rushed to Bellevue Hospital. He was expected to recover, police said.

The suspect – described as in his 20s and wearing blue jeans, a black sweatshirt with red letters and black sneakers – fled into the 14th Street / Eighth Avenue subway station, police and sources said. He remained at large late Friday.

Witness Roberto Monticello walked past the store when he heard screams and people “pushing and pushing each other.”

He saw the security guard, whom he described as “a very big guy”, fond of grabbing his wounds inside the Apple outpost.

Pictures from the scene show blood sprayed on the white floor near the bottom of the store stairs.

“You do not expect this on a beautiful day like this. You don’t expect that kind of thing, “said Monticello.

The guard was led to a back room before police and respondents arrived and took him on a stretcher, the witness said.

“Why would you hurt someone else?” Said Monticello. “It really bothered me to see someone get hurt. It really was not something I wanted to see. ”

Additional reporting by Peter Gerber