Residents of the tiny northeastern town of Dixville Notch cast the first ballots of the White House race on Tuesday, with Barack Obama and Mitt Romney each receiving five votes.

The first-in-the-nation vote, held shortly after midnight, was tied for the first time in its history, another indication of the knife's edge separating the two candidates in a race that should be decided by the end of the day.

Tanner Tillotson, 24, who cast the first ballot at 12:00 am (0500 GMT), said he voted for President Obama.

"I think (the result) is very indicative, that this is the first time in Dixville Notch's history that there is a tie. We're still a very divided nation and it will be interesting to see how the rest of the country is."

The tiny New Hampshire town, some 30 kilometers (20 miles) from the Canadian border, boasts the first vote in US elections, but is seen as more of a curiosity than a national bellwether.

Voting is usually held in the ballroom of a luxury hotel, but this year was moved to a nearby ski lodge as the building is closed for renovation.

The nearby hamlet of Hart's Location has long competed with Dixville Notch to be the first in the nation, but with more than twice as many voters, its count takes slightly longer to complete.

Tuesday's result in Hart's Location was a bit less ambiguous, with Obama getting 23 votes versus Romney's nine.

Early voting has been under way for several weeks in some states, and long lines have formed outside of polling stations as the two campaigns have carried out intensive get-out-the-vote efforts.

The Republican candidate has won Dixville Notch in every election since the tradition began in 1960, except for 2008, when Obama won.

Nationally, polls show Obama as the slight favorite, with the two candidates in a virtual tie in national polls but the president holding a narrow lead in the key swing states needed to win the all-important electoral college.

In US presidential elections the winner is not decided by the nationwide popular vote, but indirectly, based on each state's population, with the winner needing 270 out of 538 electoral votes.

The small state of New Hampshire casts just four electoral votes, but it is considered a swing state and could prove decisive in an election that may well be decided by a razor-thin margin.