EMBED >More News Videos A Philadelphia Police Officer was shot three times in the arm at 60th and Spruce Streets late Thursday night.

EMBED >More News Videos A Philadelphia Police Officer was shot three times in the arm at 60th and Spruce Streets late Thursday night.

EMBED >More News Videos Hear the police radio call that went out after an officer was ambushed and shot in West Philadelphia.

PHILADELPHIA -- A gunman ambushed a Philadelphia police officer as he sat in his marked cruiser, seriously injuring him. Chilling surveillance photos of the gunman have been obtained by ABC News.The black-and-white images show the suspect, dressed in what sources say is Muslim garb and wearing a mask, approaching the driver's side window of 33-year-old Officer Jesse Hartnett's cruiser.One image shows the man pointing a gun at the officer's vehicle, while another shows the muzzle flash as he fires. Another image shows the gunman with his arm in the vehicle.Police said the suspect, who was arrested following the shooting, confessed to shooting Hartnett in the "name of Islam" and pledged his allegiance to ISIS.Investigators also found out that the gun used by the shooter was a police firearm reported stolen in October 2013."It's just an absolute ambush," said Police Commissioner Richard Ross in a news conference early Friday morning outside of Penn Presbyterian Medical Center.Police have not commented on a possible motive for the shooting.Hartnett is a five-year veteran of the force. He suffered extensive injuries to his arm, but authorities say he was awake and alert prior to that surgery.Police say the suspect fired a total of 13 shots, three of which hit Hartnett in the arm.Hartnett was able to return fire, striking the suspect three times, police say. The suspect was arrested."I just have to tell you, when you look at the video - we have video that captured all of this - it's one of the scariest things I've ever seen," said Ross. "This guy tried to execute the police officer. It's amazing he's alive."The moments immediately following the shooting were also captured in a dramatic recording of police radio calls obtained by Action News overnight."I'm shot! I'm bleeding heavily!" Hartnett was heard saying.Ross said investigators believe the suspect is a 30-year-old man from Yeadon, and they were still working to confirm his identity.Jim Kenney, who is in his first week as mayor of the nation's fifth-largest city, said, "There are just too many guns on the streets and I think our national government needs to do something about that."His statement comes on the heels of President Barack Obama's announcement on Tuesday of his plan to tighten gun control laws.