Barack Obama greeted members of the Tampa Bay Rays in Florida
US Republican presidential candidate John McCain has accused his rival, Barack Obama, of supporting both teams playing in the baseball World Series.
The baseball championship series begins on Wednesday, and both teams - the Tampa Bay Rays and the Philadelphia Phillies - are from key swing states.
Senator McCain said Mr Obama backed the Phillies when in Pennsylvania and rooted for Tampa Bay when in Florida.
But the Obama campaign said that its candidate was a Chicago White Sox fan.
Speaking in Pennsylvania, Mr McCain said: "Now, I'm not dumb enough to get mixed up in a World Series between swing states.
"But I think I may have detected a little pattern with Senator Obama. It's pretty simple really. When he's campaigning in Philadelphia, he roots for the Phillies, and when he's campaigning in Tampa Bay, he 'shows love' to the Rays.
"It's kind of like the way he campaigns on tax cuts, but then votes for tax increases after he's elected."
'Love to the Rays'
Campaigning on Monday in Tampa, Mr Obama was joined at a rally by members of the Rays, a team that had just come from last place in the league the previous year to defeat the world champion Boston Red Sox for a place in the World Series.
He told the crowd: "I've said from the beginning that I am a unity candidate, bringing people together. So when you see a White Sox fan showing love to the Rays - and the Rays showing some love back - you know we are on to something right here."
But Obama spokesman Bill Burton said although the Democrat "said nice things about the members" of the Rays who were endorsing him, "that doesn't change his feelings about the fact that they bounced his White Sox out of the playoffs".
During the National League playoffs last week, Mr Obama said he was "going to have to root for Philly" because his campaign manager, David Plouffe, "is a fanatical Phillies fan, and I don't want him mad at me for the next few weeks".
Mr McCain supports the Arizona Diamondbacks, from his home state, who did not make the playoffs this year.
The World Series is widely followed in America, and the television audience for the last presidential debate was lower than usual because a key game was televised at the same time.
The series, which can last up to seven games, will conclude in the final full week of campaigning.