US President Barack Obama and Republican challenger Mitt Romney were locked in a tight battle for the White House Tuesday as broadcasters announced the first results from the presidential election, DPA reported.
Races in the key battleground states of Virginia and North Carolina were practically tied, according to results being tallied by broadcasters. Florida, another toss-up state, showed a slight edge for Obama, according to CNN exit polls.
After months of fierce campaigning, Obama, a Democrat, and Romney were separated by a razor-thin margin in opinion polls going into Tuesday's election, and initial results appeared to confirm those surveys.
Attention was focused on the handful of so-called swing states, where the race remained tightest and which were likely to determine the winner.
Long queues were reported at polling stations across the United States with voters waiting up to four hours in some parts of the crucial state of Virginia to cast their ballots, local media reported. Ballots were still being cast in the western US, including in swing states Nevada and Colorado.
Both candidates picked up early wins with Obama picking up the majority of votes in the liberal north-eastern state of Vermont and Romney in the reliably Republican southern state of Kentucky, according to CNN projections. Other states in the Democratic-leaning north-east had fallen in Obama's column while states in the more conservative south were breaking for Romney.
Romney was projected the winner in Indiana, handing Obama a loss in the traditionally Republican state that the Democrat had won in 2008. Obama had been the first presidential candidate in his party to carry the state since 1964 but had not been expected to do so again.
Obama was projected to win Romney's home state of Massachusetts, where Romney served as governor from 2003 to 2007 but which has voted solidly Democratic for decades.
Obama was also holding on to his home state, Illinois.
Romney made a last-minute stop Tuesday in Pennsylvania, whose large number of electoral votes - 20 - would be a prize in the state that normally votes Democratic but has a large number of conservative voters. He also visited Ohio, which no Republican has ever won the White House without, before returning to his home of Boston to watch the results come in.
Obama relaxed in Chicago, playing basketball according to one of his campaign traditions, and also visited a campaign field office where he thanked volunteers and supporters and voiced confidence he would win but also gave a nod to the team of his opponent.
"I also want to say to governor Romney, congratulations on a spirited campaign," Obama said.
"I'm looking forward to the results, and I expect that we'll have a good night," the president said.
In the traditionally left-leaning Washington suburb of Takoma Park, Maryland, most voters appeared to be picking Obama.
"I voted the donkey up and down," said Philip Lynch, a special education supervisor, referring to the longtime four-legged symbol of the Democratic Party.
Even though Obama is almost certain to win Maryland, Lynch admitted that he was "nervous" about the overall national results.
"The biggest issue is turnout," he said.
New Jersey residents affected by superstorm Sandy could vote via email or fax. In neighbouring New York, also hard-hit by the storm, voters were allowed to cast their ballots at any polling station. Paper ballots were also in use in parts of New York.
"I would imagine it's difficult for people to go to vote this morning after what happened last week in this area, but the voting process is like in the past, except for the paper ballots," said Susan Holiday, a Lower Manhattan resident.
Romney, accompanied by his wife, Ann, cast his vote in the Boston suburb of Belmont, where his family has lived for years.
His running mate, Paul Ryan, voted in his hometown of Janesville, Wisconsin. Ryan showed two of his children how voting works.
Vice President Joe Biden cast his ballot at a school in his hometown, Wilmington, in the north-eastern state of Delaware. Obama had already voted last month as part of his push to encourage supporters to cast their ballots early if possible.
US states set their own polling hours, so polling centres opened and closed in waves across the four time zones of the continental US. Montana, North Dakota, California and Idaho would be the final of the 48 continental states to vote, closing their polls at 0400 GMT Wednesday.