TMZ reports:
The victim tells us she was at a private party in Brown's suite at the Palms Hotel in Vegas early Saturday morning. She says was able to get her cellphone into the suite without his security noticing and when she took a pic of the singer, he went off, yelling
at her and punching her once in her right eye.
She says she left the party and called the cops a few hours later but was not taken to the hospital.
Law enforcement tells us they're currently investigating the incident and Chris is the suspect. We've reached out to his rep and lawyer ... so far, no word back.
Meanwhile, Chris Brown performed at Drais nightclub in Las Vegas on New Year's Day and he was looking so sexy.