ST. PETERSBURG, Florida (CNN) – The day before polls close in Tuesday’s critical Florida primary, some voters in the Miami area received automated phone calls in Spanish falsely accusing Mitt Romney of supporting an opening of relations with Cuban President Fidel Castro.

A key member of Romney’s Latin American policy team, Ambassador Roger Noriega, had been on local radio on Monday morning talking about Romney’s anti-Castro stance. “It was obviously a dirty tactic and strategy to rebut the efforts we made to let the [Hispanic] community know our position,” said Al Cardenas, Romney’s Florida state chairman.

Asked if he suspected rival John McCain, Cardenas responded, "Obviously it's a camp of one of our opponents,” later adding “I can't specifically state with certainty it is John McCain’s campaign, all I know is there are two campaigns making these calls, ours and his and these calls started immediately after our programming on that issue."

Both Romney and McCain have put out robocalls in Florida attacking each other — according to the Politico, that includes one each in the last two days, each has launched a call against the other.

On Sunday, the Romney campaign accused McCain of close ties with Democrats. “You can learn a lot about a candidate by looking at their friends, the call said. “John McCain and Ted Kennedy wrote an amnesty bill and McCain teamed with another liberal Democrat to write campaign finance reform.”

A McCain call that went out Monday went after Romney for changing his position on abortion and gay rights. "Unfortunately, on issue after issue Mitt Romney has treated social issues voters as fools, thinking we won’t catch on,” the ad says, adding, “Sorry, Mitt, we know you aren’t trustworthy on the most important issue [sic] and you aren’t a conservative.”

That call clearly indentifies its source: “Paid for by John McCain 2008.” The McCain campaign denies any involvement with the calls that link Romney and Castro.

– CNN Political Producer Alexander Marquardt