Three New York City Police Department (NYPD) officers were injured by “cop-hating mobs” outside a Brooklyn housing project on Sunday, according to a report.

The New York Post reported that at least some of the injuries the officers suffered were from “air mail,” or objects being tossed from the rooftops of the housing projects.

Police ran toward the gunfire when they heard at least six shots come from a rooftop of the housing project in the Bedford-Stuyvesant neighborhood.

“Straight up cowards!” one man in the crowd shouted at cops at just after midnight. “You don’t know how to do anything you f–king coward!”

At least 11 people were arrested by early Sunday in connection with the incident, the Post reported. Police say those people are facing disorderly conduct charges.

The three injured officers suffered non-life-threatening injuries.

Residents claim the incident started when cops used pepper spray to disperse crowds who were out barbecuing and picnicking to celebrate “Marcy Day,” an annual celebration that takes place at the housing projects.

“Everyone was just having their fun, no gang-banging… everyone sitting around, enjoying Marcy Day,” said a woman who lives in the Marcy Houses projects.

The violence against police officers comes after officers in the city faced a series of water dousing attacks over the summer.