Washington, May 23 : Republic presidential nominee Senator John McCain is set to meet with at least three potential running mates at a gathering at his ranch this weekend in Arizona, suggesting that he is stepping up his search for a vice-presidential candidate as the Democratic contest heads towards a conclusion.

Florida Governor Charlie Crist, Louisiana Governor Bobby Jindal and former Massachusetts Governor Mitt Romney, have all accepted invitations to visit McCain at his ranch in Sedona, Republican Party sources said?

After a week of campaigning, McCain is heading home on Friday for three days without a public schedule. His campaign described this as a social weekend that would include 10 couples, and as has been policy, declined to discuss any aspect of the vice-presidential search.

"We don't talk about the V. P. selection process," said Steve Schmidt, a senior adviser.

Some of McCain's associates said on Wednesday that while these would not be formal interviews, the weekend would provide McCain a chance to know some of his potential running mates in a social context. He is known as a social and gregarious candidate and senator, and his associates said personal chemistry would be a crucial consideration in his choice.

The identities of the potential running mates who have been summoned to Sedona are not a surprise. And even encouraging the perception that they are under consideration might be more a matter of appearance than political reality:

The mere impression that McCain is considering a running mate from Florida, for example, could help him in a critical state where he campaigned on Wednesday.

Still, the timing - coming as Senator Barack Obama of Illinois appears to have all but nailed down the Democratic nomination - suggested a new focus on a selection process that several Republicans said could prove critical to McCain's success in this tough environment.

McCain, arguably more than most presidential candidates in recent elections, has a lot riding on making a choice for running mate that could provide a boost to his candidacy in a tough atmosphere for Republicans.

In addition to Crist, Jindal and Romney, the McCain guest list includes some of his top political counsellors, among them Charlie Black, a senior strategist, and Senator Lindsey Graham of South Carolina, his frequent travelling companion and probably his closest colleague in the Senate. Also on hand will be at least one senior business executive prominent in McCain's circle, Frederick W. Smith, the chairman of FedEx.

McCain himself has said his choice of a running mate would draw particular scrutiny from voters given McCain's age; he is now 71, or "as old as dirt," as he likes to joke, while quickly adding that he is in good health.

More than that, with Obama's selection as his party's nominee now almost assured, McCain is contemplating a contest against an energized Democratic electorate after a campaign that has highlighted race and gender issues.

The meeting, which was not disclosed publicly, is taking place on a weekend after Mr. McCain releases his health-care records. The release of those records on Friday is itself a high-profile event that could - by design or not - draw attention away from the gathering.

McCain said this month that he had assembled a list of about 20 potential running mates. He said he had not decided when he would make a decision; his aides made clear that he would keep the process as closely held as possible.

Among the other potential running mates are Minnesota Governor Tim Pawlenty and Rob Portman, the former director of the Office of Management and Budget who had been an Ohio Congressman.

Crist, a fairly popular first-term governor, has been included on various lists of potential running mates for McCain, whom he endorsed shortly before Florida's January primary, which effectively helped McCain claim the nomination.

Crist said Wednesday that he and McCain had not discussed the prospect, not even at a fund-raiser in Miami that the two attended Tuesday night.

The McCain campaign, Crist said, has not solicited the kind of personal information typically requested to vet possible running mates.

As Governor of Florida, Crist, 51, would bring obvious assets to the Republican ticket, beginning with his popularity in a state that is almost always an electoral battleground
- and where Obama appears to be struggling.

Crist's relative youth could also be an asset for McCain, who has made clear that age will be a consideration in his search for a running mate.

Romney, the former chief executive who ran unsuccessfully for the Republican nomination in 2008 and who was born in Michigan, has made no secret of his desire to join McCain's presidential ticket.

Romney's M. B. A. skills, and business background - including running the 2002 Salt Lake City Olympic Games - could address concerns about McCain's ability to manage a struggling economy.

Romney has also proven himself as a prolific fund-raiser, though he spent enormous sums of money during his campaign and still could not beat McCain.

Jindal, who was born in Baton Rouge, La., to a family that had just arrived there from Punjab, India, took office in January after serving three years in the House of Representatives.

In a race with four candidates, Jindal, who was born a Hindu but converted to Roman Catholicism as a teenager, won 54 percent of the vote after campaigning as a social conservative, opposing human embryonic stem cell research and abortion in any form, and favouring teaching "intelligent design" in schools as an alternative to evolution. (ANI)