Two teenage boys were injured, including one critically, in a shooting in North Philadelphia on Monday, police said.

The shooting happened outside a convenience store near the intersection of Girard Avenue and Carlisle Street just before 5 p.m., police said. 

A 17-year-old boy was shot in both arms, both legs and his torso and is in critical condition at Temple University Hospital, Philadelphia Police Chief Inspector Scott Small said. A 16-year-old was shot in both of his legs and was placed in stable condition. 

The two teens who were shot were standing outside the store in a small group of three to five people when police say multiple shooters fired into the crowd. More than 50 shots were fired, Small said. 

Officers on patrol nearby heard the gunshots and responded within seconds, he said.

Small called the shooting a "very, very brazen crime." A surveillance camera on a nearby business captured the entire incident, and police have obtained the video, Small said. He added that police could find more video from the area during the investigation. 

Three suspected shooters were seen running northbound on Carlisle Street from the scene, Small said.

It's unclear what led to the shooting.