Obama v Romney: US votes in tight White House race
Tens of millions of Americans have begun voting to decide whether to re-elect President Barack Obama or hand the job to Republican Mitt Romney.
The voting ends a hard-fought race that began nearly two years ago and has cost more than $2bn (£1.3bn).
Polls show the race is neck and neck, although the president holds a slender polling lead in vital swing states.
Adam Brookes reports.
For in depth coverage as the US goes to the polls: BBC US election special report