Justin Bieber -- Making Young Girls Cry (VIDEO)

A group of young girls tried to get a pic with Justin Bieber, but instead they got a car door slammed in their faces ... reducing one of the fans to tears.

The girls claim they'd been waiting for hours on a NYC sidewalk, and when Bieber bee-lined for his SUV ... they started begging for the photo op.

Problem is ... their timing was off. JB was trying to talk to a friend at the same time they were asking for the shot, he got pissed -- and snapped at them. Watch happened next, but needless to say they did NOT get a pic.

Still, we gotta ask ...