WASHINGTON, Nov. 6 (Xinhua) -- U.S. presidential polls in key swing state of Ohio were closed at 7:30 p.m. 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.
U.S. TV networks have projected Obama to win the "deep blue" Vermont, giving him 3 electoral votes, while Romney is projected to win the "deep red" Kentucky, Indiana, South Carolina and West Virginia with 33 electoral votes.
A candidate needs to win 270 of the total 538 electoral votes to win the presidency.
Obama was projected by Fox News on Tuesday evening to win swing state Pennsylvania, getting the state's 20 electoral votes. Other swing states remain too close to call, including Virginia, Florida and Ohio.
Ohio offers 18 electoral votes. 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 a.m. (1000 GMT).
Although figures have yet to come in, U.S. 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.
Despite the smooth-going of the elections, there are also sporadic complaints of computer malfactions, as well as human errors.
Some polling machines in Pennsylvania, Ohio were said to have changed voters' choice from one candidate to another.
In New Jersy, voters in some areas struck by superstorm Sandy are asked to cast their votes via email but only find that the email address given to them was crammed and their ballot emails were bounced back.
While in Florida, local television reported voting was delayed by a printing machine malfunction.
Hundreds of voters in Florida and the U.S. capital city Washington were also reported to have received automated calls telling them to vote on Wednesday.