Mitt Romney on Tuesday said that Sen. Marco Rubio (R-Fla.) is being “thoroughly vetted” as a vice presidential candidate, rejecting reports that the freshman senator is not being considered for the job.

“Marco Rubio is being thoroughly vetted as part of our process,” Romney said, according to multiple accounts from reporters on the ground in Michigan.

Romney said reports to the contrary were “entirely false” and came from sources that have “no knowledge” of his team’s selection process.

The statement is the first time Romney has confirmed or denied vetting any prospective candidates. Romney’s campaign has kept a tight lid on the process despite rampant speculation about who is and isn’t on the candidate’s short list.