President Obama has been campaigning in Colorado ahead of the Democratic Party's convention next week in North Carolina.

Before addressing thousands of supporters, Obama stopped off at the The Buff restaurant in Boulder, where he chatted to customers enjoying brunch.

Obama told supporters his Republican presidential rival Mitt Romney offered no new ideas when he spoke at the Republican Party's convention in Tampa, Florida last week. At the mention of the GOP, there were boos from the crowd.

"Don't boo, vote," Obama told the audience.

"Despite all the challenges we face in this new century, what they offered over those three days was an agenda that was better suited for the last century.

"It was a rerun, it could have been on 'Nick-at-Nite', we've seen it before."

"You might as well have watched it on a black and white TV with some rabbit ears," Obama continued.