The transit officer is in critical, but stable condition. The two civilians were residents of the building where the gunman holed up are reported to be in stable condition at Temple University Hospital. The identities of the victims have not been released.
The responding officers have taken cover and the Philadelphia SWAT team has arrived at the scene. The police have surrounded a building where the shooter is believed to be holed up on the third story. The shooting reportedly began at 7 p.m. local time.
The shooter remains unidentified but it is believed that he died from a self-inflicted gunshot wound. It remains unclear what prompted the shooting spree.