BURLINGTON, Mass. – President Barack Obama and Republican Mitt Romney are embarking on a week heavy with travel through battleground states and appeals to key constituencies, with both campaigns wrangling over unrest in the Middle East and who is best equipped to rejuvenate the economy.

Both candidates are courting voters in a series of must-win states and reaching out to a number of voting groups that could determine the election, from working-class white voters in states like Ohio and Wisconsin to Latino voters in Florida.

Obama and Romney have dueled for an advantage on foreign policy, with attention focused on unrest in the Middle East in reaction to an anti-Muslim video that led to the storming of several U.S. diplomatic posts and the killing of four Americans, including the U.S. ambassador to Libya.