The third and final debate of the US presidential campaign has begun, with Democratic incumbent Barack Obama and his Republican rival Mitt Romney due to discuss foreign policy.
The candidates shook hands on stage at Lynn University in Boca Raton, Florida before their last head-to-head, which pundits said may prove decisive, with opinion polls predicting an extremely close vote on November 6.
With 15 days to go until Americans vote on November 6, the stakes are high as the pair run neck and neck in the polls.
Al Jazeera's Alan Fisher, reporting from Boca Raton, said that foreign policy is a key issue for voters.
"The idea that Americans don't pay attention to foreign policy [has been] blown apart by another poll which says 92 per cent of them are interested or very interested in America's place in the world," he said.
"Both men know the importance of this and are willing to bank any advantage they can get this late in the campaign."
According to a NBC/Wall Street Journal poll, which came out on Sunday, both men are tied at 47 per cent.
The nationwide poll, which was conducted after last Monday's presidential debate, re-inforced the perception of the race as a cliffhanger.
It showed "a little bit of a lead" for Romney among the critical "battleground" states as a group, NBC correspondent Chuck Todd said on the network's "Meet the Press" programme.
Among a larger sample of registered voters, Obama led Romney 49 per cent to 44 per cent, the Wall Street Journal said in a report on the poll on its website.
The final debate is crucial for both candidates as Romney entered the first debate in Denver on October 3 with a strong performance which changed the course of the race, vaulting him back into an even position in the polls with Obama.
Then, Obama was ruled the narrow winner of the second encounter on October 16 when he got the better of Romney in a testy exchange.
His campaign halted the slide but it was not enough to edge ahead in the polls.
Monday's debate is the last major chance for Romney and Obama to be seen by millions of voters before Election Day.
More than 60 million viewers watched each of their previous two encounters.
Despite a reputation for being wooden, Romney has shown an ability to rise to the occasion and perform well on stage.
Foreign policy credentials
The incumbent Democrat seems to have the upper hand on foreign policy since he has been in charge of US national
security for nearly four years.
Obama gets credit for the mission that led to the killing of Osama bin Laden and for pulling troops from Iraq.
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Romney, a former governor of Massachusetts, whose trip abroad in July to London, Jerusalem and Poland was marked by missteps.
Romney has to assure voters he is a credible alternative to the president on the world stage.
Romney has promised to tighten the screws over Iran's nuclear programme and accused Obama of "leading from behind" as Syria's civil war expands and setting up a politically timed exit from the unpopular Afghanistan war.
The Republican is likely to bring up a report that the United States and Iran agreed in principle to hold bilateral negotiations to halt what Washington and its allies say is a plan by the Islamic Republic to develop nuclear weapons.
The debate will be divided into six segments: America's role in the world; the war in Afghanistan; Israel and Iran; the changing Middle East; terrorism; and China's rise.