World

President Barack Obama sharply challenged Mitt Romney on foreign policy as the two presidential rivals squared off in their third and final debate with the race in a dead heat two weeks before Election Day.

Obama used Monday night's debate to criticize Romney's support for beginning the war in Iraq, for opposing his plans to withdraw troops from Iraq, for inconsistent stances on Afghanistan and for opposing nuclear treaties with Russia.

"Every time you've offered an opinion, you've been wrong," Obama said.

Romney, a former Massachusetts governor, responded that "attacking me is not an agenda" for dealing with a dangerous world. He accused Obama of sending the wrong signals to Iran's leaders by showing weakness in the Middle East.

"We're four years closer to a nuclear Iran," he said. Still, Romney stressed that war is a last option to prevent Tehran from developing a nuclear weapon, softening the hawkish tone that had been a hallmark of his campaign.

If and how the debate would affect the Nov. 6 presidential election was not clear. Foreign policy, the theme of the debate at Lynn University, in Boca Raton, Florida, has not been a major issue in a race centred on the U.S. economy. But both candidates were determined to appear to be strong leaders, rallying their supporters and winning over the remaining undecided voters.

There was none of the finger-pointing and little of the interrupting that marked their debate last week, when Obama needed a comeback after a listless performance in their first meeting on Oct. 3. Still, the two men frequently sniped at one another.

Romney, though, was more measured than Obama, agreeing with the president on a number of issues, perhaps seeking to appear more moderate to centrist voters who may determine the election's outcome. He barely mentioned what has become the hottest foreign policy issue in the campaign: the Obama's administration's handling of the attack on the U.S. Consulate in Benghazi, Libya, that killed the U.S. ambassador and three other Americans.

Obama, from the opening moments, wasn't as subdued. He said Romney would reinstate the unpopular foreign policies of President George W. Bush. He accused him of frequently changing positions on how he would have handled Iraq and Afghanistan and jabbed at Romney's comments during the campaign that Russia is the United States' No. 1 geopolitical foe.

"Governor, when it comes to our foreign policy, you seem to want to import the foreign policies of the 1980s, just like the social policies of the 1950s and the economic policies of the 1920s," Obama said.

Romney described an Obama trip to the Middle East early in his presidency as an "apology tour" that bolstered U.S. adversaries while bypassing close ally Israel. Obama called that accusation the "biggest whopper" of the presidential campaign."

The debate was moderated by veteran newsman Bob Schieffer of CBS News.

With the final debate behind them, both men are embarking on a two-week whirlwind of campaigning. The president is slated to speak in six states during a two-day trip that begins Wednesday. Romney intends to visit two or three states a day.

Already four million ballots have been cast in early voting in more than two dozen states.