Chris Brown -- Exercises Right to Remain Silent on Phone-Snatching Accusation

Chris Brown was asked squarely for the first time -- Did he steal a Florida woman's cell phone?

Brown -- who was in Orlando -- was mum on the subject, but the freelance photog had some choice words for the silent Brown.

24-year-old Christal Spann filed a police report last Sunday -- claiming the singer snatched her phone right out of her hands when she tried to take a picture of him ... then drove away.

We posted a video this morning, showing an agitated Christal describing the incident to police ... just moments after the alleged phone-jacking.