Donald TrumpDonald TrumpRepublicans giving Univision the cold shoulder: report Could Trump and the Democrats make 'ObamaCare Lite' any lighter? Week ahead: House Intel chair under fire over Trump surveillance claims MORE is stepping up his attacks on Mitt Romney, telling voters he's much wealthier than his Republican critic.

"He's an elitist, but I don't consider him elite because I'm much richer than he is," Trump said at a rally in Warren, Mich., a day after Romney made a highly publicized speech laying out his case against the GOP presidential front-runner.

The New York billionaire went on to say that a Gucci store he owns in Manhattan is worth more than Romney.

Trump also slammed Romney for his failed 2012 presidential campaign, repeatedly calling him a choke artist.

"In one speech, he lost 47 percent of the voters," he said, referring to remarks Romney made in 2012 suggesting that 47 percent of the country was dependent on the government.

"This is not a smart guy," Trump added.

"He is a dumb guy. I've always said he's a dumb guy," he added later.

In his speech Friday, Romney called Trump a fraud and said he was leading the nation "into the abyss."