Gallery: American voters head to polls

US citizens are lining up to cast their votes, as the US President Obama and Republican challenger remain neck-and-neck.

Voters (photo credit: REUTERS/Chris Keane )
(photo credit: REUTERS/Chris Keane )
WASHINGTON- Americans started to vote in a presidential election on Tuesday with polls showing US President Barack Obama and Republican challenger Mitt Romney neck-and-neck in a race that will be decided in a handful of states.

Polling stations opened across the eastern United States and parts of the Midwest as dawn broke. At least 120 million Americans were expected to vote on giving Obama a second term or replacing him with Romney.As Americans headed to voting booths, campaign teams for both candidates worked feverishly at the last minute to mobilize supporters to cast their ballots. Polls will begin to close in Indiana and Kentucky at 6 p.m. EST (2300 GMT) on Tuesday, with voting ending across the country over the next six hours.
The presidential contest is now likely to be determined by voter turnout - specifically, what combination of Republicans, Democrats, white, minority, young, old and independent voters shows up at polling stations.