Donald Trump criticized Mitt Romney (R-Mass.) and Jeb Bush (R-Fla.) Saturday during his speech at the Freedom Summit in Iowa.

The conservative real estate mogul spoke at the summit in Des Moines hosted by Steve King (R.-Iowa), and spent some time talking about the two absent potential presidential candidates, Politico reported. Trump labeled Romney and Bush as weak candidates and pointed out what he considers to be their flaws.

"It can't be Mitt -- he ran and failed. He failed," Trump said.

Although he personally likes Romney, Trump bashed the former governor of Massachusetts' health care reforms he set up while in office, along with his "47 percent" comment he made during the 2012 presidential campaign.

Trump said Romney choked and ruined his opportunity to take down a weak president. He added that Bush would not make a good candidate either.

"The last thing we need is another Bush," he said. He then criticized Bush's embrace of the Common Core educational standards and immigration reform.

Trump also blamed Bush's brother, former President George W. Bush, for the election of President Obama, according to the Los Angeles TimesTrump said he was considering running for president in 2016.

Other potential presidential candidates spoke and will speak at the Freedom Summit in the coming days. Retired neurosurgeon and tea party favorite Ben Carson talked about immigration reform during his speech.

Wisconsin Gov. Scott Walker spoke about the gains he made in his state regarding protection laws for gun owners and reducing regulations for small businesses and farms.

Upcoming speakers include New Jersey Governor Chris Christie, 2008 candidate Mike Huckabee and 2012 candidate Rick Santorum.

In addition to Romney and Bush's absence, Florida Sen. Marco Rubio and Tennessee Sen. Rand Paul did not attend the summit.