8:50 AM PT -- The folks at Power 106 say Chris was yelling at a guy who was in a section of the arena where he didn't belong, and they support what he did.
Chris Brown was full of piss and vinegar at a charity basketball game Sunday, getting in a heated, prolonged argument with someone in the stands ... intense enough for cops to get involved.
Chris was at the Power 106 Celebrity Basketball Game at USC, when he became visibly upset. It's hard to hear what the beef was about because of loud music, but you hear one of the USC cops say, "I don't care who's here, get it straight."
Chris also refused to stand during Tank's rendition of the National Anthem. He didn't kneel ... he sat. And he was anything but solemn ... yukking it up.