Voters are heading to the polls Tuesday in the United States to elect the next president, members of the House of Representatives and one-third of the Senate.

The governorships of 11 states, Puerto Rico and American Samoa are also up for grabs on election day.

More than 238 million people are eligible to vote, but only 178 million, or 75 percent, are registered to vote.

Poll results released over the past few days showed an extremely tight presidential race, prompting analysts to predict that the outcome may not be known until the early morning hours on Wednesday.

Voters are being asked to decide whether to give Democratic President Barack Obama four more years in the White House or to hand the presidency to his Republican rival, former Massachusetts Gov. Mitt Romney.

Obama wrapped up his campaign on Monday in Iowa, while Romney plans to hold Election Day rallies in the battleground states of Ohio and Pennsylvania, which could determine who ends up in the White House.

Romney and his wife, Ann, voted Tuesday morning in the Boston suburb of Belmont, where the couple lives.

Obama cast his ballot during the early voting period in Chicago on Oct. 25.

Voters in the hamlet of Dixville Notch, New Hampshire, were the first to cast ballots in the country, with Obama and Romney ending up tied at 5-5.

This was the first time that a presidential election ended up tied in Dixville Notch, which began its tradition of casting the first votes in 1960, an election official said.

More than 31 million Americans cast ballots at early voting sites or by mail in 34 states and the District of Columbia. EFE