The feud between Donald Trump and Jeb Bush appears to be intensifying.

Donald Trump listens as Jeb Bush (R) fields a question during the first Republican presidential debate on August 6, 2015 in Cleveland, Ohio. (Photo by Scott Olson/Getty Images)

Bush's 2016 presidential campaign has released a video that shows Trump talking more like a Democrat than a Republican.

And while campaigning in Miami, Bush said Trump only resorts to insults because he can't talk about issues.

As Bush put it, "If you're not totally in agreement with him, you're an idiot, you're stupid, you have low energy," and the like.

Trump tweeted in response: "Yet another weak hit by a candidate with a failing campaign."

Heading into the next debate, Trump continues to hold a double digit lead over most of his rivals for the nomination.

The next debate is scheduled for Sept. 16 on CNN.