John McCain is hosting several officials considered to be potential running mates at his Arizona retreat over the Memorial Day weekend -- but his campaign insists the gathering is just a social affair.

The presumptive GOP presidential nominee plans to host two-dozen guests, including Louisiana Gov. Bobby Jindal, Florida Gov. Charlie Crist and former Massachusetts Gov. Mitt Romney.

They are all politicians whose names have been thrown around as potential vice presidential picks. South Carolina Sen. Lindsey Graham, a McCain confidante also expected to attend, said former White House budget director Rob Portman and Kansas Sen. Sam Brownback -- two more potential McCain candidates -- are scheduled to make an appearance as well.

But Graham said the guests are arriving for a "social weekend" only.

McCain adviser Mark Salter said the weekend gathering is "purely social" and that no VP vetting is on the agenda.

It will be the first visit to Sedona, Ariz., for Jindal, Crist and Romney.

Jindal spokeswoman Melissa Sellers confirmed the weekend plans but downplayed any political implications.

"The governor has met with the senator many times before and discussed the challenges facing the Gulf Coast region as communities continue to rebuild," she said. "The governor looks forward to joining Senator McCain and his other guests this weekend, and he values this as another opportunity to meet with a national leader, and the potential next president of the United States, to discuss issues important to the future growth of Louisiana."

McCain said more than a month ago that he was in the "embryonic stages" of selecting a running mate for the fall campaign, but since then, neither he nor aides have disclosed additional information. Advisers have only confirmed that McCain is heading up the search committee himself.

His weekend visitors undoubtedly will fuel speculation.

Romney dropped out of the Republican presidential race in February after it became apparent it would be near impossible to topple McCain in the convention delegate race. He endorsed McCain a week later and pledged to help him win the nomination.

Since then, McCain has praised Romney repeatedly as someone who is certain to continue playing a large role in the GOP. Romney, for his part, has suggested that he'd accept a vice presidential slot, though some Republicans privately speculate that he's looking ahead to a possible repeat run in 2012.

Crist, 51, provided a major boost to McCain before Florida's Jan. 29 primary with his endorsement.

Elected governor in 2006, he has been seen as a moderate Republican. He has championed efforts to curb climate change, and former President Clinton praised him for his efforts to restore voting rights of felons who have completed their sentences. Crist also pushed for a law that requires a paper trail in state elections.

Jindal, 36, son of Indian immigrants, was elected governor of Louisiana in October 2007, three years after being elected to the House, where he was credited with playing an important role in his state's recovery from Hurricanes Katrina and Rita.

Before serving in Congress, he was secretary of Louisiana's health department, and he was an assistant secretary in the U.S. Department of Health and Human Services.

A source close to McCain dismissed some of the speculation about his guests, characterizing Jindal as "too young" and "too inexperienced" for VP. And with a smile, the source said sarcastically: "And Mitt Romney -- you think he's a serious pick?"

McCain completes his week of campaigning and fundraising Thursday in Stockton, Calif., and is scheduled to fly to Sedona Thursday night.

McCain has hosted several friends (and potential VP candidates) at his Sedona home over the last couple months. During the last weekend in February, he hosted a few other names in the VP hunt including: Utah Gov. Jon Huntsman, North Carolina Sen. Richard Burr, Minnesota Gov. Tim Pawlenty and South Dakota Sen. John Thune.

Click here to read about how political oddsmakers view McCain's potential running mates.  

FOX News' Mosheh Oinounou and Trish Turner and The Associated Press contributed to this report.