Despite widespread speculation that U.S. Sen. Marco Rubio, R-Fla., is among Mitt Romney's top picks for the Republican vice presidential nomination, the freshman senator has not yet been vetted by the Romney campaign, according to a report from ABC News.

Rubio has not been asked to complete any questionnaires or turn over any financial documents to the campaign, both typical parts of the vetting process, unnamed Republican sources told the news agency. While it is possible that Rubio, who for months has sidestepped questions regarding his vice presidential ambitions, may still be a contender, the report notes Romney appointed a long-time aide to run his vice presidential search nearly two months ago.

Some Republicans have pointed to Rubio -- a young, Cuban-American who is a favorite among tea party conservatives -- as Romney's best chance of securing Florida, a crucial swing state, and making inroads with Hispanics ahead of the November presidential election. Romney has frequently praised Rubio in recent months while on the campaign trail, describing the senator's story as the son of Cuban immigrants as an example of the American dream.

The Romney campaign has refused to comment on the vice presidential search.

Late last month, Virginia Gov. Bob McDonnell, another Romney backer often cited as a vice presidential contender, revealed he has not been asked to turn over any vetting documents to the Romney campaign.