Mariah Carey hired extra security after Nicki Minaj threatened to shoot her.

The American Idol star has confirmed her fellow judge menaced her with gun violence during their explosive argument on the set of the talent show on Tuesday, and she is worried about the "unpredictable" rapper's next move. Mariah contacted chat show host Barbara Walters, who read out a statement on The View which revealed several staff members had heard Nicki quip, "If I had a gun I would shoot the b***h."

Barbara related, "She said she is very concerned, she's with her twins, she doesn't feel that anything would happen, but Nicki is unpredictable and Mariah says she can't take a chance and has hired extra security. Nicki has not apologized, but they were together in meetings... during which Nicki said, 'I love you, but we might fight again!' Mariah said at this point she doesn't feel comfortable emotionally but she will continue with the show because she loves mentoring the contestants."

The pop divas' catfight - which saw Nicki hurl a torrent of abuse at Mariah - was caught on camera and left everyone "shocked" and "embarrassed," but it seems the singers won't be calling a truce anytime soon.

Nicki has now launched a Twitter war, accusing the "Hero" singer of wanting a "pity party" as well as bragging about being considered the best judge "since Simon [Cowell]." The rapper wrote in a series of furious tweets," Tried to keep quiet but let's go!!!! I thought we resolved it yesterday but I see u want ur pity party to continue. So I'm bout to po dot tea. I don't call tmz n Barbara Walters cuz I stand on my own two feet. Never needed an army. God is good. Insecurity is as cruel as the grave. I guess it hurts 2 have the producers tell u to ur face that nicki is the best judge we've had since simon. Awww, poor u. Keep them lies cmn. (sic)"

Fellow judge Keith Urban also weighed in on the fight, joking he felt like "the UN" caught in the middle of things.