BARACK Obama is back in the White House after winning the 2012 US presidential election.

BARACK Obama is back in the White House after winning the 2012 US presidential election.

America’s first black leader beat Mitt Romney in the closely fought battle tonight to secure another four years as the most powerful man in the world.

As US TV networks reported he had won, Obama tweeted: "This happened because of you. Thank you."

He then tweeted: "Four more years."

Early indications suggested a long drawn-out election after tight exit polls in the swing states of Ohio and Virginia.

But the momentum started to swing in the early hours to Obama as he took Pennsylvania and Wisconsin.

That meant Romney's only way to the Oval office was to take the crucial states of Ohio, Virginia and Florida to get over the target of 270 electoral college votes.

But Obama picked up the vital state of Ohio according to projections to end Romney’s bid to be the first Mormon to lead the States.

During the night the president's campaign made sure people did not leave voting queues early, urging its supporters on Twitter to #stayinline.

Earlier Obama and Romney had each grabbed early wins in states traditionally loyal to their parties.

Using exit polls, US television networks projected victories for Republican Romney in Alabama, Georgia, Indiana, Kentucky, Mississippi, Oklahoma, South Carolina, Tennessee and West Virginia.

Democrat incumbent Obama has picked up Connecticut, Delaware, Illinois,Maryland, Massachusetts, New Jersey, Rhode Island, and Vermont - all states in which he was favourite.