Donald Trump: 'Nice' Carly Fiorina Did 'Terrible Job' at Hewlett-Packard

ABC News' Martha Raddatz spoke with the GOP frontrunner.

Trump’s comments represent another attack in an ongoing war of the words between the two Republicans, both of whom have cited their business acumen as positives in their run for the presidency. Fiorina, who seemed to avoid attacking Trump earlier this year -- she said he was tapping into an existing anger -- has taken the real estate mogul to task recently over his comments on Fox News anchor Megyn Kelly.

Speaking today on “This Week,” Fiorina said, "You know, it's not clear to me that Donald Trump is a Republican, first of all, based upon his willingness to run a third party bid and the -- some of the positions that he's taken."