Someone vandalized Pittsburgh police headquarters, one of its precincts and a marked cruiser on the North Side over the weekend.

Officers discovered early Sunday that the letters “ACAB” — a possible acronym, police said, for “All cops are (expletive)” — had been spray-painted on the police bureau’s headquarters on Western Avenue in the city’s Chateau neighborhood, according to Emily Bourne, a police spokeswoman.

Less than a mile away, similar graffiti appeared on the side of the Zone 1 station on Brighton Road in the city’s California-Kirkbride neighborhood.

And someone used a graffito-marked brick to smash the windshield of a marked Pittsburgh police cruiser outside the same precinct house.

As well, a civilian vehicle parked in the North Side station lot sustained what Bourne called “superficial body damage.”

No arrests have been made.

A bureau statement released Sunday said police were “aware of several incidents of vandalism” but did not elaborate.

Photographs posted online showed a Zone 1 exterior wall marked with the letters “ACA” in black spray-paint.

Bourne called the graffiti the likely work of a tagger — a person marking public spaces with a signature or pseudonym.

“While the Pittsburgh Bureau of Police fully respects individuals’ right to free speech, acts of vandalism are unacceptable and will not be tolerated,” the bureau said in a statement.

Police are investigating and reviewing security camera footage from the weekend, Bourne said.