At a Saturday rally in Boone, Iowa, Trump blasted Paul as being an "ineffective guy" and weak on immigration and national security issues. He claims Paul is attacking him because his polls numbers remain quite low and he needs media attention.

Trump currently stands at nearly 30 percent compared to Paul's two percent, according to the latest Real Clear Politics average polling.

During his speech, Trump blasted critics who say he's picking fights with his fellow Republicans and pointed to primary voters who prefer his "aggressive tone and tremendous energy."  

The latest feud began Thursday when Paul, referring to Trump, said "I don't really think there's anything conservative about him and I think he's selling us a bill of goods. And so I think we need to be very careful that we don't succumb to celebrity and all of the sudden get a fake conservative that turns out to be a big government Republican."