The New York Times reported McCain, the presumptive Republican nominee, had asked Gov. Charlie Crist of Florida, Gov. Bobby Jindal of Louisiana and Mitt Romney, the former Massachusetts governor and a onetime rival for the Republican nomination, to join him at his ranch in Sedona, Ariz., for a Memorial Day outing, along with some of the senator's top political counselors.

Politico, a Washington publication, reported that the three invitees shouldn't be considered a "short list" for vice president.

The McCain campaign called it a social weekend, declining to discuss the vice presidential question directly, Politico said. Some associates said the meetings wouldn't be formal interviews but would show some potential running mates in a social context.

McCain said earlier he had assembled a list of about 20 potential running mates. Observers said McCain's move indicated he was beginning to narrow the choices as the Democratic Party nomination race appeared to be nearing a conclusion.