Chicago police said the incident happened at about 3:19 p.m. on Monday in the 1800-block of N. Harding Avenue.
Police said a 23-year-old woman was outside when she got into an argument with an unknown man.
CPD said she was in an alley when the altercation happened.
The man then pulled out a gun and struck the victim in the face, police said.
The suspect then got into white pickup truck that appeared to be waiting for him. They fled eastbound.
CPD said the victim declined EMS.
No other information was available.
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Editor's Note: It was initially reported that the altercation happened on The 606 trail. The story has been updated to add the correct location.