nicki minaj & mariah carey*The drama between Nicki Minaj and Mariah Carey is getting deeper and just plain scary.

Minaj’s rant on the “American Idol” set in Charlotte Tuesday went way beyond name-calling (see video below).

Sources connected with the production tell TMZ she threatened Mariah Carey’s life.

Our sources say … in the heat of the argument, Nicki said, “If I had a gun I would shoot her.”

The alleged threat was not captured on the video obtained by TMZ.  But this is interesting … if you listen to the audio closely, 11 seconds in you hear Nicki say to Mariah, “Off with your head! Off with your head!”

A source close to Nicki says the singer calls B.S. on the death threat allegation against Mariah.