President Barack Obama and Republican rival Mitt Romney are embarking on a travel-heavy week through battleground US states, 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 key 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 and viewers of a popular Spanish-language television network.
The winner of the US presidential election is not determined by national popular vote, but by a series of state-by-state contests, making victory in battleground states such as Ohio and Florida particularly important.
Mr Obama and Mr Romney have duelled 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 US diplomatic posts. Mr Romney's campaign has also pointed to the events in Egypt and Libya as evidence of national security weakness from the Obama administration. Susan Rice, the US ambassador to the United Nations, defended the administration on television talk shows, calling the critique a "very empty and baseless charge of weakness".
Mr Romney and Mr Obama have also tangled over China, each accusing the other of supporting policies that would move American jobs overseas. Mr Romney released a television advertisement last week assailing Mr Obama for "failing American workers" and ignoring unfair trade practices by China. Mr Obama responded with an ad accusing Mr Romney of outsourcing jobs to China when he worked in the private sector.
Mr Obama kicks off his week in Ohio, with stops planned in Cincinnati and Columbus. The President is raising campaign cash in New York on Tuesday, followed by events in Florida on Thursday, Virginia on Friday and Wisconsin on Saturday - all states that he carried in the 2008 election.
Mr Obama is making his first trip to Wisconsin in months and his most pronounced pitch to voters there since Mr Romney chose Wisconsin congressman Paul Ryan as his vice presidential running mate. Wisconsin has not voted for a Republican presidential candidate since President Ronald Reagan in 1984 and is considered one of Mr Romney's most enticing electoral targets.
Mr Romney's itinerary includes fund-raising stops in the Los Angeles area along with outreach to key Latino voters, including an address to the United States Hispanic Chamber of Commerce and an interview with Spanish-language television network Telemundo, which interviewed Mr Obama last week. Mr Romney is also expected to hold fund-raising events in Utah and Texas before heading to Florida for similar events later in the week.
Both campaigns have competed vigorously for voters in eight states likely to decide the election - Ohio, Florida, Virginia, Iowa, New Hampshire, Colorado, Nevada and North Carolina. The states have dominated the candidates' attention in travel and advertising.
Mr Romney spent several hours at a Boston-area hotel with advisers on Sunday, prompting speculation that he was preparing for the forthcoming presidential debates. The first debate, considered a crucial showdown between him and Mr Obama, will be held on October 3 in Denver, Colorado.