Barack Obama has been re-elected as US President - winning crucial swing states to secure a victory over Republican challenger Mitt Romney.
The Democrat gained the 270 electoral college votes needed to win a second term in office.
Obama told ecstatic supporters the "best is yet to come" in a victory speech in his home city of Chicago.
The crowd chanted "four more years" as the President arrived on stage with wife Michelle and daughters Malia And Sasha.
He praised his family, revealing he had never loved his wife more and commending his "smart, beautiful" daughters.
Obama also congratulated opponent Romney on a "hard fought campaign" and said he would work with the former Massachusetts governor to take the country forward.
The Democrat also vowed to revive the economy but warned "progress will come in fits and starts".
Republican Mitt Romney earlier conceded defeat and phoned the President to congratulate him on his election victory.
The former Massachusetts governor urged his supporters to pray for Obama - who now faces the task of rejuvenating America's economy.
In his five minute concession speech in Boston, Romney said he and running mate Paul Ryan had "given our all" to the presidential campaign.
ITV News Correspondent Paul Davies reports on Romney's defeat:
Obama secured a convincing victory over Romney despite earlier polls suggesting the pair were neck and neck.
Under the electoral college system - which allots votes to states according to population size - Obama secured 303 while Romney is on 206.
Florida's 29 electoral college votes have yet to be declared, with Obama holding onto a slender lead in the sunshine state.
The President also appears to be leading in the popular vote, according to reports.
After it became clear Obama had won the election, the President tweeted "four more years" with a picture of him hugging Michelle.
Prime Minister David Cameron - who is currently on a tour of the Middle East - sent his congratulations to Obama.
The election also saw the Democrats maintain their control over the US Senate and the Republicans keep control of the House.
Read ITV News' analysis on Obama's presidential victory:
- Washington Correspondent Robert Moore on what to expect from Obama's second term.
- International Editor Bill Neely's analysis on Romney falling short.
- Economics Editor Richard Edgar's analysis on Obama's economic challenges ahead.
- Middle East Correspondent John Ray's analysis on what Obama's victory means for Israel.