6 November 2012
Last updated at 16:10 ET
Tens of millions of Americans are voting to elect the next US president and turnout is crucial, with polls suggesting a neck-and-neck race between Democratic President Barack Obama and his Republican challenger Mitt Romney.
As the months of campaigning came to an end, the US began voting in the early hours of the morning. Though more than 30 million voters had already cast their ballots before Tuesday's polls opened, with more than 30 states allowing either absentee voting or early voting in person.
The first to cast their ballots were the 10 registered voters in the small village of Dixville Notch, New Hampshire, who waited until the stroke of midnight to vote. The result was a dead heat, with five votes going to Barack Obama and five to Mitt Romney.
With the contest expected to be extremely close, swing states like New Hampshire are key battlegrounds.
Mitt Romney cast his vote in Belmont, Massachusetts, with his wife Ann. He is continuing to campaign on voting day with a series of last-minute rallies planned.
President Obama is spending the day visiting campaign offices in Chicago. He is not voting on Tuesday, having voted early in his adopted home state of Illinois.
In Austin young voters lined up to cast their vote across the street from the University of Texas. Both candidates are relying on enthusiasm and a high turnout among their supporters.
Vice-President Joe Biden waits to vote in Greenville, Delaware.
Mr Biden's rival Republican vice-presidential candidate Paul Ryan studies the ballot papers with his daughter before casting his vote in Janesville, Wisconsin.
On the Eastern Seaboard, the continued fallout from storm Sandy has disrupted voting plans. Temporary polling stations like this one in Queens, New York, have been set up where original sites were destroyed or damaged.
Voters are also electing the new members of the US House of Representatives, as well as a third of the seats in the 100-member US Senate and 11 state governors.
Actors wearing Mitt Romney (left) and Barack Obama masks arrive at a party in Berlin, just one of many events around the world attended by US expats who are gathering to watch events unfold.
Polls will start closing in eastern states at 18:00 EST (23:00 GMT) and a winner could become clear within hours.