It happened at South 58th Street near Norfolk Street around 9 p.m. Sunday.
Police say a 33-year-old man and woman had stopped at the water ice stand.
When they got out of their truck, the two were approached by a male suspect.
"They engage in some sort of discussion which turns into an argument and shortly thereafter the male pulls out a gun and fires at least four times at the gunshot victim," Philadelphia Police Inspector D.F. Pace said.
The man was shot once in the stomach. He was taken to Penn Presbyterian Medical Center in critical but stable condition.
Police say the woman was not injured.
Real-time surveillance cameras in the area captured part of the incident which showed the suspect fleeing on foot.
No arrests have been made.
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