Billionaire businessman Donald TrumpDonald TrumpTrump pledges federal help after deadly southern storms Meetings crowd Trump's first Monday in office Clinton: Photos from women’s march ‘awe-inspiring’ MORE on Monday fired back at a Republican senator who recently said the mogul has no chance of being president. 

Trump took aim at Sen. Lamar AlexanderLamar AlexanderSenate committee vote on DeVos postponed Cheney calls for DeVos to be confirmed ‘promptly’ With Trump pick Tom Price, cool heads can prevail on health reform MORE (Tenn.), the chairman of the Senate Republican Conference, who said Sunday that Trump is "famous for being famous" and "not going to be president."

"In all fairness, he's not someone that's exactly at the top of this list," Trump said of Alexander during an interview on Fox News. "He's done very little over the years and he does not seem to be an important player in Washington, unfortunately."

Members of both political parties have questioned the wisdom of the outspoken Trump's flirtations with a presidential bid. But that has not stopped the host of NBC's series "The Apprentice" of testing the waters.

He sent a business adviser to Iowa on Monday to meet with officials ahead of a large gathering of potential GOP candidates in the early primary state.

Trump told Fox he would decide whether he'll run for president before June. If he runs, Trump said he would not seek Alexander's endorsement.