Mariah Carey (L) and Nicki Minaj in the video for “Up Out My Face”

*OK, here we go with the back and forth now in war between Nicki Minaj and Mariah Carey

We can see this is starting to get old already. But you just want to know every juicy detail, we must report.

It seems Mariah Carey was the one who fired the first shots in her diatribe against “American Idol” co-judge with Nicki Minaj. She’s accused of calling the rapper a “bitch” multiple times, according to sources close to Minaj.

According sources, Miss Nicki is adamant … in the moments before the TMZ video begins (see below), Mariah repeatedly berated her … until Nicki finally had enough and exploded.

We’re told … Nicki feels Mariah has been wasting everyone’s time by constantly praising herself instead of focusing her energy on critiquing the contestants.

One source tells us, “She keeps bringing up how many records she’s sold, name dropping people she’s worked with, how many tours she’s done, and how many Grammys or awards she’s won … Nicki is tired of it.”

We shall keep you appraised of future back and forths. Promise.