Updated 6:17 p.m. ET

Mitt Romney told reporters in Michigan that Florida Sen. Marco Rubio is being looked at as his possible running mate, adding that a news story out today about the Tea Party favorite not being vetted was "entirely false."

"Marco Rubio is being thoroughly vetted as part of our process," Romney said during a campaign stop in Holland, Mich.

ABC News reported this morning that the freshman senator was not being vetted to be Mitt Romney's running mate. The report cited "knowledgeable sources."

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The ABC report said Rubio "has not been asked to complete any questionnaires or been asked to turn over any financial documents typically required of potential vice presidential candidates." It went on to say that it was "possible that Rubio may yet be asked to go through the vetting process."

"There was a story that originated today apparently at ABC based upon reports of supposedly outside unnamed advisers of mine. I can't imagine who such people are," Romney said. "But I can tell you this: They know nothing about the vice presidential selection or evaluation process. There are only two people in this country who know who are being vetted and who are not, and that's Beth Myers and myself.

"The story was entirely false," he said. "Marco Rubio is being thoroughly vetted as part of our process."

Myers is a longtime trusted adviser to Romney and served as his chief of staff when he was Massachusetts governor.

Rubio has refused repeatedly to say whether he is being vetted, out of "respect for the process" and Romney.

Rubio's name is frequently mentioned as a possible VP contender, and former Florida governor Jeb Bush is among those who have been touting the Tea Party favorite as a top pick. Rubio has been highlighted as someone to watch ever since he was elected to the U.S. Senate in 2010.

(Contributing: Jackie Kucinich in Holland, Mich.)