Taylor Swift's "bad blood" with fellow pop superstar Katy Perry looks set to get a lot worse.

Perry on Wednesday took to Twitter, where she has more followers than anyone else in the world, to take down Swift in a row set off by the nominations for the MTV Video Music Awards.

Rapper Nicki Minaj had voiced outrage that her "Anaconda" failed to be nominated for Video of the Year. She suggested that the music industry was biased against her as an African-American woman and preferred female stars "with very slim bodies."

Swift, who received the most nominations for the August 30 awards, responded by inviting Minaj to join her on stage if Swift wins.

"I've done nothing but love and support you. It's unlike you to pit women against each other. Maybe one of the men took your slot," tweeted Swift, who has cast herself as a feminist.

Perry -- who memorably sang "You're gonna hear me roar" -- entered the fray a day later with pointed criticism of Swift, without using her name.

"Finding it ironic to parade the 'pit women against other women' argument about as one unmeasurably capitalizes on the takedown of a woman," she wrote to her nearly 73 million Twitter followers.

Perry, in turn, wrote that she wished that Rihanna had been nominated for "Bitch Better Have My Money," which came out on the last day of eligibility for the awards.

Perry and Swift, often considered the era's two leading women in pop, have long been rumored to have a poor relationship but it has rarely spilled into the open.

Swift was nominated for Video of the Year for "Bad Blood," which depicts her as an action hero.

Swift has said that she wrote the song -- with the lines "Now we got problems / And I don't think we can solve them" -- about another pop star whom she accused of undercutting her by hiring people who had been working for her.

While Swift did not name her villain, she was widely believed to be referring to Perry.
Source: AFP