U.S. President Barack Obama and his Republican challenger, Mitt Romney, are set to debate for a third and final time Monday, this time on foreign affairs.

For months during the long campaign leading to the November 6 election, surveys showed voters giving the Democratic incumbent a strong foreign policy edge over Mr. Romney, especially for President Obama's approval of the 2011 raid in Pakistan that killed Osama bin Laden, mastermind of the 2001 terrorist attacks on the United States.

The Republican candidate's foreign affairs expertise has largely been limited to overseas business deals he helped negotiate during his long career as a venture capitalist.

However, newer surveys show that Mr. Romney has cut sharply into the president's perceived advantage on foreign affairs. Mr. Romney has pointedly criticized the White House's changing explanations about the September 11 raid on the American consulate in Benghazi, Libya that killed four U.S. diplomats.

Aside from debating the Benghazi attack, the candidates are likely to discuss a variety of other foreign affairs issues. Among them are the bin Laden raid, China's role in the world economy, Mr. Obama's plan to end American military involvement in the war against the Taliban in Afghanistan by late 2014, the deadly conflict in Syria, rising tensions between Israel and Iran over Tehran's nuclear development program, and relations with Russia.

Fifteen days ahead of the election, several surveys show the race virtually tied, with a new NBC News/Wall Street Journal poll finding the race deadlocked at 47 percent each.

Monday's 90-minute debate is being held in the closely contested southern state of Florida and will be moderated by Bob Schieffer of CBS News.