Barack Obama tells rally that Mitt Romney was untruthful during debate

U.S. President Barack Obama came out swinging against Republican rival Mitt Romney on Thursday after a lackluster performance in their first debate forced the Democrat's aides to talk of "adjustments" to his campaign.

Dressed casually in khakis and a jacket, Obama told a rally of some 12,000 people the former Massachusetts governor was untruthful during their 90-minute debate, which most observers said the Republican won.

"When I got onto the stage, I met this very spirited fellow who claimed to be Mitt Romney," Obama said.

"But it couldn't have been Mitt Romney, because the real Mitt Romney has been running around the country for the last year promising $5 trillion in tax cuts that favor the wealthy. The fellow on stage last night said he didn't know anything about that."