President Barack Obama has won a second term in the White House, defeating Republican contender Mitt Romney after securing several key battleground states.
Speaking in Chicago as jubilant supporters chanted "four more years," Obama congratulated Romney on a hard-contested campaign.
"We may have battled fiercely," Obama said, "but it's only because we love this country deeply."
Obama also thanked supporters who had campaigned to achieve the victory. "We have picked ourselves up, we have fought our way back and we know in our hearts that, for the United States of America, the best is yet to come."
Romney had already officially conceded defeat in a brief address at his campaign headquarters in Boston, Massachusetts. He told supporters that he had called Obama to congratulate him on his victory.
The president secured victory in the key state of Ohio, putting him over the 270 electoral votes needed to secure a second term in the White House.
US networks had projected an Obama sweep of the traditionally liberal states of the mid-Atlantic, the northeast and the West Coast. The president also made inroads in the Midwest, winning his home state of Illinois and the seat of the once-ailing American auto industry, Michigan.
Obama has won the battleground states of Wisconsin, the Midwestern home of Romney's running mate Paul Ryan, and Iowa. The president also secured the mid-Atlantic state of Pennsylvania, the northeastern state of New Hampshire, Virginia, and Colorado.
Republican contender Romney, meanwhile, had a predictable victory march through the staunchly conservative states of the American south. The former Massachusetts governor and venture capitalist also advanced through the plains states north into the Dakotas and parts of the mountain west.
Romney was the winner in Indiana, a traditionally center-right state where Obama had a surprise victory in 2008 against Senator John McCain. The governor also won the southern state of North Carolina, a state which in 2008 bucked historical trends and went for Obama last time around.
Obama has secured 303 electoral votes and thus the presidency, with votes still to be counted for the final battleground state of Florida. Romney trailed the president with 203 electoral votes. The president stood at 49 percent in the popular vote, with the former governor coming in at 49 percent as well.
The US president is elected not by the popular vote, but instead by an electoral college. The candidate who wins the popular vote in a state typically also wins all of its electoral votes. In order to make it to the White House, a candidate must secure 270 out of 538 electoral votes.
Meanwhile, US broadcasters have projected that the Republicans will retain control of the US House of Representatives. The Democrats are expected to maintain their majority in the Senate.
slk, hc / rc (AP, AFP, Reuters)