Barack Obama has won the 2012 US Presidential elections and is going to remain in the White House for another four years.

"Four more years," Obama tweeted. "We're all in this together. That's how we campaigned, and that's who we are. Thank you.This happened because of you."

Democrat America cheered and celebrated the victory at the end of a very tight and strenuous campaign.

Democrats have also retained control of the Senate in the crucial congressional elections.

People flocked to the streets across the US and a crowd of jubilant Obama supporters gathered in front of the White House, echoing Obama's tweet by chanting "Four more years! Four more years!"

Obama will hold his post-election speech at McCormick Place in Chicago, Illinois.

Romney is also expected to make a speech at the Boston convention centre, but the atmosphere there is completely different, as it is now almost certain that the former governor of Massachusetts, who has not conceded defeat, has lost the race for the White House.