Cop Shoots at Pack of Dogs Attacking Man in the Street in Harrowing Video

An unsettling scene unfolded in Philadelphia -- where a police officer had to shoot a canine after a pack of dogs started to maul a poor man in the street, in broad daylight.

This disturbing footage is making the rounds online -- and it shows the beginning, middle and end of a violent incident in the City of Brotherly Love that recently went down ... where at least 4 dogs got loose and started ganging up on a guy, which was all caught on camera.

It's unclear what exactly led up to this ... but the video starts by showing the pooches trotting down the sidewalk, where a cop car is already there and seemingly observing the situation.

The man recording claims that one of the dogs -- 3 of which were pit bulls -- had apparently just attacked somebody else ... and before you know it, they're all going after another person -- a man across the street, who gets circled by them and knocked to the ground.

All the dogs start biting at him as he tries to fend them off, and others even try coming to his aid to no avail -- at which point, the officer gets out of his car and approaches cautiously.

There are people around pleading for the cop to fire his gun -- and he eventually does, hitting the largest dog ... which runs away and falls over, convulsing on the ground.

Philly PD says the officer who did this has been placed on administrative leave, and that he tried using his siren at first to distract the animals. The dog that died was actually a Cane Corso -- and the three other pit bulls fled the scene. No word on their whereabouts.