Obama wins four more years

The incumbent garnered 50.3 per cent of the popular vote to Mr Romney's 48.1 per cent with just Florida left to declare.

The electoral college system translated to a barnstorming 303 seats for the Democrat compared with 206 for the Republican, while it was unclear where Florida's 29 seats would go.

Mr Obama swept to victory in key battleground states like Ohio and Wisconsin, which were must-wins for Mr Romney's campaign.

But the Democratic vote was down on 2008 when he took 52.9 per cent to John McCain's 45.6 per cent.

And despite the proclaimed closeness of the race, around 13 million fewer people voted than last time around - although the 118m counted so far will go up slightly as more results come in.

Chinese President Hu Jintao telephoned Mr Obama to congratulate him. Mr Romney had pledged to label China a currency manipulator, which many feared would spark a trade war.

British Prime Minister David Cameron welcomed the news that his "friend" had kept the presidency.

And Syrian rebels said they hoped Mr Obama would now be free to start sending them weapons.

But state TV in Venezuela reminded Mr Obama that he had "various promises unfulfilled," including closing US gulag Guantanamo Bay and taking action on environmental matters.

Mr Obama will continue to have a tricky time steering his legislation through Congress as Republicans kept a solid majority in the House of Representatives.

The Democrats retained their narrow control of the Senate, adding the USA's first openly gay senator Tammy Baldwin to their complement.

Republican House speaker John Boehner insisted that the vote made it clear the president had no mandate for raising taxes on the rich.

The right-wing Tea Party movement made a number of gains in high-profile races in Texas and Nebraska but Todd Akin lost his attempt to unseat the Democrat incumbant in Missouri.

Mr Akin sparked a storm of criticism and disbelief earlier this year when he insisted that women's bodies have way of avoiding pregnancy in cases of "legitimate rape."