United States President Barack Obama and Republican Mitt Romney have clashed over their economic proposals in the first of three presidential debates.
Wednesday's 90-minute debate at the University of Denver is the first time voters across the US have the chance to see Mr Obama and Mr Romney on stage together.
Despite the long presidential campaign, the pair are virtual strangers and have met just three or four times in the past, the BBC reports.
In the opening exchanges, Mr Romney, repeatedly denied that he planned a $US5 trillion tax cut.
He accused Mr Obama of planning to raise taxes on small businesses, while the president said his rival's plan repeated disastrous policies of George W Bush.
Mr Obama has opened up a narrow lead in the race over the past month. He is ahead of Mr Romney in national polls and in many recent polls conducted in the swing states that will decide the election on 6 November.
In a wide-ranging debate about the economy, Mr Obama criticised Mr Romney's plans as "top-down economics".
Mr Romney, the former Massachusetts governor, characterised Mr Obama's approach as "trickle-down government".
Mr Romney pledged not to reduce taxes for wealthy Americans, saying Mr Obama had misrepresented his tax plans on the campaign trail. He hit out at the president for failing to cut the budget deficit in half as he pledged in 2008, and insisted that America must not allow itself to go down the path of Greece or Spain.
Clashing repeatedly with moderator Jim Lehrer over the time clock, Mr Romney said that in order to reduce the budget deficit he would repeal Mr Obama's 2010 healthcare law and cut subsidies to US public television, among other unspecified programmes.
And he assailed Mr Obama over his plans to eliminate overseas tax breaks, telling him he had "picked losers" by funnelling money into failing industries.
Mr Obama deflected criticism of his fiscal management, highlighting Mr Romney's primary-season pledge not to raise taxes. He characterised Mr Romney's approach to deficit reduction as "unbalanced" because he had previously ruled out tax increases.
"There has to be revenue in addition to cuts," Mr Obama countered, calling for an end to "corporate welfare" tax breaks for oil companies and corporate jets. "The magnitude of the tax cuts you are talking about, governor, would result in severe hardship for people."
Barack Obama and Mitt Romney disagreed over the future of Medicare, the government healthcare scheme for over-65s.
Mr Romney said that Mr Obama's "Obamacare" reform law of 2010 had increased health costs and kept small businesses from hiring.
He questioned why the president had spent so much time and energy pushing that reform early in his tenure rather than repairing the economy and creating jobs.
Mr Romney reprised disputed claims that the president's law cut $US716 billion from Medicare, but praised and defended a plan he himself had previously signed as governor of Massachusetts that is widely hailed as the model for Mr Obama's law.
Mr Obama, meanwhile, said he had been moved to push for the law by stories of voters' healthcare woes and that his plan had kept insurance companies from cutting off coverage from sick people.
"This was a bipartisan idea, in fact this was a Republican idea," Mr Obama said, adding he was now proud of the once-derisive nickname "Obamacare".