According to the report, four others were injured after the Monday night shooting that occurred in the Kingsessing section of Philadelphia.
One of those killed is believed to be a teenager, police said, adding that a suspect, wearing a bulletproof vest and armed with a rifle and a handgun, was taken into custody shortly after the shooting.
At least six victims were taken to Penn Presbyterian Medical Center and two were taken to the Children's Hospital of Philadelphia, media reported.
The shooting comes just a day after two people were killed and 28 others were injured in a mass shooting in Baltimore during a block party.