WASHINGTON - US presidential polls in key swing state of Ohio were closed 7:30 pm eastern time (0030 GMT Wednesday), half an hour after polling stations were shut down in Virginia, another critical swing state.

Americans across the country went to polls on Tuesday to choose the next president between incumbent Barack Obama and Republican nominee Mitt Romney.

Apart from Virginia and Ohio, polls have also ended in Georgia, Indiana, Kentucky, South Carolina and Vermont.

US TV networks have projected Obama to win the "deep blue" Vermont, giving him?three electoral votes, while Romney is projected to win the "deep red" Kentucky, Indiana, South Carolina and West Virginia with 33 electoral votes.

Virginia, with 13 electoral votes, remains too close to call, as exit polls showed a neck-and-neck race in the state. A candidate needs to win 270 of the total 538 electoral votes to win the presidency.

Ohio, with 18 electoral votes, was also too close to call. Vice-President Joe Biden, Romney and running mate Paul Ryan all went there in a last-ditch effort to woo voters.

The Election Day began with midnight voting in a pair of small towns in New Hampshire, and expanded across the nation after 5 am (1000 GMT).

Although figures have yet to come in, US media outlets are reporting heavy turnout in the elections. Early exit polls showed 73 percent of the voters were white, 13 percent African American, 10 percent Latino and 3 percent Asian.

According to exit poll results released by CNN, 6 in 10 voters say economy is the top issue facing the nation, with healthcare and deficit running distant second and third.