Attention Upper West Siders: watch your backs... and your fashion choices.

The '90s may be back in style, but the NYPD's 24th Precinct is not impressed by your fanny packs. And, in a move that would make Joan Rivers proud, they even tweeted about how hideous they are.

advertisement | advertise on newsday

"Summer=crowds. Protect your stuff. We @ 24 r not the fashion police but fanny packs present a special case," @NYPD24Pct tweeted, along with a very fashion police-like composite photo of a woman rocking a black, printed fanny pack in two different ways.

In one, she wears the fashion faux pas in question on her back. "Hideous and vulnerable," the caption says. In the other, she wears it facing front: "Hideous but protected."

To quote another '90s fashion icon: "Way harsh, Tai."

Maybe this really is about safety, or maybe someone's been watching E! re-runs in the stationhouse. All we know is, we'll think twice before getting dressed to walk down W. 100th Street from now on.