THE BEEF IS ON: MARIAH SNIPES AT NICKI NICKI GOES BALLISTIC CAUGHT ON TAPE

Nicki Minaj derailed the "American Idol" auditions in Charlotte, North Carolina Tuesday, after swearing at Mariah Carey and threatening, "I'm gonna knock you out" ... but Mariah FIRED RIGHT BACK with insults of her own. In the footage, obtained by TMZ, Nicki is clearly furious ... shouting, "I told them I'm not f*ckin' putting up with her f**kin' highness over there." Mariah can be heard saying, "“Oh why, WHYYYY .do I have a three year old sitting around me?” Carey continues, "I can’t see my kids, because you decided to act like a little crazy bitch and go all around the stage.” Sources say Nicki later threatened to "knock out" Mariah ... but she said it before the video starts. It all went down while the two were sitting at the judge's table ... with Keith Urban sitting in between them and Randy Jackson sitting on the far end, next to Mariah. We're told the whole thing exploded over a disagreement over a contestant's performance. Listen closely as you play the video ... you'll hear Nicki Get this s**t in self control. Get in control. Get in control. Randy Settle down, settle down. Nicki Don't lose your head. Don't lose your head (inaudible). Don't tell me I'm a gangster. Nicki (inaudible) every 5 minutes. So every time you patronize me, I'm-ma take it back, and if you've got a f**king problem, handle it. Nicki I told them I'm not f**kin' putting up with her f**king highness over there. Figure it the f**k out. Figure it out. Mariah Oh why, WHYYYY .do I have a three year old sitting around me? Nicki I'm not gonna sit here every f**king minute to have you come down and harass me every minute everyday. Mariah I can’t see my kids, because you decided to act like a little crazy bitch and go all around the stage. Mariah is talking back at Nicki but it's hard to hear what she's saying. According to our friends at MouthToEars.com, producers ended the auditions for the day so the two judges could cool down. We've confirmed that happened. Big wigs on the show seem uncharacteristically upset by the blow up. It seems producers are worried about Mariah and Nicki co-existing for the long haul.