WASHINGTON -- President Barack Obama and Republican challenger Mitt Romney frantically sought to make their closing arguments in an incredibly close race for the White House but were forced to overhaul their campaign plans to avoid a massive hurricane churning up the U.S. Atlantic Coast.

Wary of being seen as putting their political pursuits ahead of public safety, the two presidential candidates reshuffled their campaign plans as the storm approached with only nine days remaining before Election Day on Nov. 6.

Heading into the final full week of the campaign, Democrats claim math is on the president's side. Republicans insist Romney has got the momentum in pursuit of the 270 electoral votes needed for victory.

Both candidates were loath to forfeit face time with voters in battleground states like Virginia that are likely to be afflicted when Hurricane Sandy, a winter storm and a cold front collide to form a freak hybrid storm.

Obama cancelled campaign stops Monday in Virginia and Tuesday in Colorado to monitor the storm but planned to go forward with other events Monday in Florida and Ohio, with former President Bill Clinton at his side, before returning to Washington. He planned to return to Ohio on Wednesday with stops in Cincinnati and Akron, followed by a Thursday swing through Springfield, Ohio, Boulder, Colorado, and Las Vegas.

Obama got an update Sunday from disaster relief officials before speaking by phone to affected governors and mayors.

"Anything they need, we will be there," Obama said. "And we are going to cut through red tape. We are not going to get bogged down with a lot of rules. We want to make sure that we are anticipating and leaning forward."

An opportunity for Obama to demonstrate steady leadership in the face of crisis was offset by the risk that the federal government, as in past emergencies, could be faulted for an ineffective response, with the president left to take the fall.

Romney cancelled three stops in up-for-grabs Virginia on Sunday, opting instead to campaign with running mate Paul Ryan in Ohio before heading Monday to Wisconsin, where Romney has chipped away at Obama's lead.

"I know that right now some people in the country are a little nervous about a storm about to hit the coast, and our thoughts and prayers are with people who will find themselves in harm's way," Romney told several hundred supporters crowded into a field house at the University of Findlay, the second of three Sunday rallies.

Romney's campaign confirmed Sunday that he would not travel to New Hampshire on Tuesday as planned. The campaign had already cancelled a Monday event in New Hampshire featuring Romney's wife, Ann. Advisers say further travel changes are likely as they monitor the storm's progress.

Vice-President Joe Biden cancelled a Monday event in New Hampshire. "The last thing the president and I want to do is get in the way of anything. The most important thing is health and safety," Biden said.

Ryan planned to leave Ohio at midday for three stops in Florida. His Tuesday schedule, however, shifted him to stops in Colorado instead of Virginia.

The prospect that bad weather could hinder early voting and get-out-the-vote efforts is vexing to both campaigns.

In Virginia, one of the most competitive states in the race, election officials eased absentee voting requirements for those affected by the storm.

Getting voters to the polls -- whether early or on Election Day -- is one of the few elements of the race still in the candidates' control. Although Romney and Obama are in a close contest for the popular vote, the president continues to have the upper hand in the most contested states.

The U.S. president is not chosen by the nationwide popular vote, but in state-by-state contests that allocate electoral votes. Each state gets one electoral vote for each of its seats in the House of Representatives, as determined by population. Every state has two seats in the Senate, guaranteeing an additional two electors. That means there are 538 electoral votes, including three for Washington, D.C., of which the winning candidate must have 50 per cent, plus one, or 270.

Obama is ahead in states and Washington, D.C., representing 237 electoral votes; Romney has a comfortable lead in states with 191 electoral votes. The contest is too close to call in the nine decisive battleground states: Colorado, Florida, Iowa, Nevada, New Hampshire, North Carolina, Ohio, Virginia, and Wisconsin.

While Romney and Obama are deadlocked in national polls, there were signs that the burst of momentum Romney achieved after the first presidential debate had waned in Ohio, Virginia and elsewhere.

Voters in many states, including Florida, Iowa, Nevada, and Ohio, are already casting ballots early, and about one-third of the electorate will have voted before Election Day. Both candidates were pushing hard to get their supporters to the polls to bank insurance votes before Election Day.

In addition to scrambling to tweak schedules, the campaigns were shifting manpower and pumping millions of more dollars into TV ads in the decisive battleground states. Deep-pocketed outside groups are paying for direct mail, automated phone calls and other get-out-the-vote efforts.

Total campaign spending has exceeded $2 billion, making this presidential race the most expensive in the history of electoral politics.

In the campaign's final stretch, Romney has struck a more moderate tone as he courts women and independents. Obama has countered by emphasizing the far-right conservative positions Romney took on such issues as abortion to secure the Republican nomination.

With each candidate claiming he is best able to revive the struggling economy, the latest jobs report due Friday from the Labor Department will shine an 11th-hour light on economic progress four days before most people vote. Last week, the most recent snapshot of economic growth showed the U.S. economy was growing but at a tepid rate.