WASHINGTON — Barack Obama's campaign is concerned that Hurricane Sandy could hurt the president's re-election chances by keeping voters from going to the polls, a top strategist said Sunday.

Republican challenger Mitt Romney has surged in the polls since an October 3 televised debate, eroding Obama's slender lead in key swing states like Ohio, where a new poll shows them in a 49 to 49 dead heat.

"Obviously we want unfettered access to the polls because we believe that the more people come out, the better we're going to do," David Axelrod told CNN.

"And so to the extent that it makes it harder, you know, that's a source of concern," he said.

With the storm due to hit late Monday or early Tuesday, both Obama and Romney have scrambled to revamp their schedules in the final stretch of a campaign that is already very close.

Obama canceled two campaign events next week and moved up a visit to Florida on Sunday so he could be back in Washington before the so-called "Frankenstorm" makes landfall on the US East Coast.

"I don't know how all the politics will sort out. It depends on how scenarios are impacted," Axelrod said.

"And so the best thing we can do is focus on how we can help people during this storm and hope that it all clears out and that by the next weekend we'll be free of it and people can focus on the election."