Several hours after the US networks called the presidential election for Barack Obama, Mitt Romney has just delivered his concession speech in Boston. In a short and gracious address, he told the crowd that he had made the traditional phone call to "congratulate" Obama on his victory. Romney added:

This is a time of great challenges for America and I pray the president will be successful in guiding our nation.

I so wish that I had been able to fulfill our hopes to lead the country in a different direction but the nation chose another leader.

With Obama already topping 300 Electoral College votes (he required 270 to win), and Florida still to declare, his margin of victory is looking as large as the final swing state polls suggested. After he secured re-election by taking Ohio, the US President tweeted [2] the above photo, with the message "four more years".

However, with the Republicans retaining control of the House of Representatives, he will soon be forced to confront the threat of renewed political gridlock.