UPPER EAST SIDE — A security guard at the Metropolitan Museum of Art was struck over the head with a bottle by a man who got upset over a painting he said was crooked, according to the NYPD.

The suspect went up to the guard inside the Met at 6:15 p.m. on March 3 and told him that a painting was hanging crooked on the wall, police said.

"The response [from the security guard] wasn't to his liking," a police spokesman said, so the suspect clobbered him with the bottle.

The victim was taken to the NewYork-Presbyterian Weill Cornell Medical Center in stable condition with a cut to his head, police said.

The suspect — shown in a surveillance video released by police sporting a long beard while standing at a kiosk inside the museum — fled the scene and has not yet been arrested, according authorities.

Police described him as 20 to 25 years old, standing 5-foot-8 and weighing 150 pounds.

"We are thankful that no visitors were injured in this incident, and the security officer suffered only minor injuries," a spokeswoman for the Met said. "We are grateful for the professionalism of our security team, and are working in coordination with the NYPD on this incident.”

No works of art were damaged in the incident.

Anyone with information in regards to this incident is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477).