U.S. President Barack Obama told the American people "the best is yet to come" after he defeated Republican challenger Mitt Romney to win re-election.
Obama thanked his cheering supporters in an early morning victory speech at his Chicago headquarters, telling them the "task of perfecting our union moves forward." He said "we are an American family and we rise or fall together as one nation and one people."
Obama also thanked his Republican challenger, Romney, and his vice presidential running mate, Paul Ryan, for waging a hard fought campaign. He said although he and Mr. Romney strongly disagreed on the issues, they both shared a deep love for the country.
Shortly before the president spoke, Romney conceded the race in a speech before a crowd of disappointed supporters in Boston, Massachusetts, the state he once governed. He congratulated Mr. Obama on his election victory, saying "this is a time a great challenge for our nation, and I pray the president will be successful in guiding our nation."
The latest projected results from Tuesday election have Mr. Obama, a Democrat, winning 303 electoral votes and Mr. Romney with 206 Electoral College votes. A candidate needs at least 270 electoral votes to win the presidency.
Obama won in the District of Columbia and 25 states, including the battleground states of Ohio, Virginia, Iowa, New Hampshire and Pennsylvania. Romney won in 23 states including North Carolina and Indiana, which both went for Obama last election. Another key battleground state, Florida, remains too close to call.
The candidates made a final push for support Tuesday as voters waited in long lines at polling places. Some sporadic problems were reported, and both candidates dispatched lawyers to monitor the voting for any irregularities.
The Justice Department had nearly 800 observers in 23 states to respond to any allegations of fraud.
After a year-and-a-half of campaigning, three debates and thousands of televised campaign ads, nationwide pre-election surveys had the two candidates in a virtual deadlock.
U.S. presidential elections are not decided by the national popular vote, but rather by the Electoral College system, developed more than 200 years ago, in which each of the 50 states' influence on the outcome is roughly equivalent to its population. The winner needs 270 electoral votes to win the White House.
Voters were also electing all 435 members of the House of Representatives, and 33 of the 100 members of the Senate.
Projections Tuesday show Republicans will hold onto control of the House of Representatives while Democrats will stay in charge of the Senate.
Millions of Americans cast ballots in early voting in the last month. Obama voted several days ago in his home city of Chicago, and spent Tuesday there. He conducted interviews for broadcast in key states and played basketball with friends, one of his Election Day traditions. He also called voters from a campaign office.
Romney, a one-time venture capitalist, voted Tuesday morning in Massachusetts, the northeastern state he once governed but where Obama won. He also made a final push for votes in the key states of Ohio and Pennsylvania.