Donald Trump Says Jeb Bush 'Embarrassed by What's Happening' The real estate mogul also said Rep. Paul Ryan is too weak on immigration.

 -- Front-runner Donald Trump says that fellow GOP presidential candidate Jeb Bush keeps attacking him because the former Florida governor is “embarrassed” that he has failed to gain traction on the campaign trail and in the polls.

“Well, look, Jeb has had a very hard time,” Trump said via telephone on “Good Morning America” today. “He’s way down in the polls. He’s doing very poorly. He’s embarrassed by what’s happening. So he has to attack me to try to get his numbers up.

“The last thing we need is another Bush. We’ve seen what happens. The last thing we need is another Bush and he understands that and the voters understand that. You know, to compare me to Michael Moore; that one hasn’t happened before.”

Bush has defended his brother George W. Bush against Trump's saying that the former president is to blame for the 9/11 terrorist attacks.

"That Trump echoes the attacks of Michael Moore and the fringe left against my brother is yet another example of his dangerous views on national-security issues," Jeb Bush wrote in an op-ed published Tuesday by the National Review. "This is a man who has previously stated he would prefer Hillary Clinton had led negotiations on the nuclear agreement with Iran."

Bush has also slammed Trump for his lack of policy credentials.

"Donald Trump is not a serious candidate as it relates to foreign policy,” he told Fox News last week, adding that he doesn’t believe Trump has the capability of creating strategy overseas.

Trump also today weighed in on Rep. Paul Ryan, who announced overnight that he will run for speaker of the House if the entire Republican Party unites around him.

Trump confessed to liking Ryan personally, but thinks the Wisconsin congressman can be stronger on immigration. “Had we had strong immigration, my policies, you may not have had the World Trade Center’s coming down,” Trump said. “I feel very very strongly about immigration and we have to be strong on illegal immigration. He is not there.”