Mitt Romney issued a stinging assault on President Barack Obama, mocking his "petty attacks and silly word games" in a speech in Florida.

The Republican presidential nominee spoke to 8,500 people at a rally in Daytona Beach, where he accused US President Barack Obama of "petty attacks".

"The Obama campaign has become the incredible shrinking campaign. This is a big country with big opportunities and great challenges and they keep on talking about smaller and smaller things," Romney said.

He added that the Democrats had, "no agenda for a second term".

Romney, the former governor of Massachusetts, has closed the gap between him and President Obama in the opinion polls, after giving a strong performance in the first presidential debate.