A Philadelphia police officer who responded to a call to assist another officer whose patrol car was shot at was injured Saturday night when he was knocked to the ground by an ATV rider, police said.

Police received a 911 call about a person with a gun shortly after 10:15 p.m. at 800 Brill Street in the Summerdale section of Northeast Philadelphia. A Second District officer heard multiple gunshots upon his arrival and then heard two shots hit his patrol car on the passenger side, police said.

A 15th District officer who had arrived to help attempted to stop a male on an all-terrain vehicle but was knocked down by the rider and hit his head. He was taken to Jefferson Torresdale Hospital in stable condition, police said.

The ATV rider was apprehended a short distance away and a handgun was found in his possession, police said.

No other details were available Sunday.