The New Nation - Internet Edition

Agency, Washington

The US presidential candidates are to focus their efforts on key swing states on Sunday as the 18-month-long election campaign draws to a close.

Republican John McCain will appear on stage twice in Pennsylvania, while Democrat Barack Obama will speak in Ohio three times. McCain's running mate Sarah Palin will also hold three Ohio rallies.

Ohio, which narrowly voted Republican in 2004, is seen as a must-win for McCain in Tuesday's election.

Under the system used in US presidential elections Ohio carries 20 electoral votes, making it one of the largest states where polls show the result could still go either way.

Pennsylvania, where McCain will hold two rallies on Sunday morning, is another crucial state. It boasts 21 electoral votes and voted Democratic in 2004.

Analysts say McCain, 72, needs to win in Ohio to stand a chance of reaching the White House, while Obama needs to hold on to Pennsylvania for the Democrats if his poll lead is to be translated into a result on election day.

After spending Saturday campaigning in traditionally conservative states brought into play by Obama's poll lead, both candidates will use Sunday to return to more usual election battlegrounds.

McCain showed his lighter side on Saturday night, appearing on the high-profile TV comedy show Saturday Night Live.

He played on his reputation as a maverick and the reality of being outspent on the campaign trail by Obama.

"I'm a true Republican maverick: a Republican without money," McCain joked, pretending to introduce a sale of campaign-related products on shopping channel QVC - chosen, he told viewers, because the McCain-Palin campaign could not afford nationwide network TV coverage like Obama.

He appeared in good spirits as he appeared on the show beside comedian Tina Fey, performing her much-acclaimed impersonation of Mrs Palin.

Campaigning in Virginia earlier, the Arizona senator told voters: "We can and will win.

"I'm not afraid of the fight, I'm ready for it and you're going to fight with me," he told voters.

For his part, Obama, 47, used a nationwide radio address to repeat his message of "change": "If you give me your vote on Tuesday, we won't just win this election - together, we will change this country and change the world."

Both campaigns have thousands of volunteers working flat-out manning phone banks, handing out brochures and knocking on doors as election day approaches.

Join us on 4 November to follow the news as America votes, including:

Live text updates through the day and night, with input from BBC correspondents around the US.

Results as they come in, on a live updating map, from midnight GMT Streaming video of the BBC election night programme in Washington Analysis from BBC North America editor Justin Webb in Washington, and Gavin Hewitt and Matthew Price at the candidates' HQs.

Obama, who saw his lead narrow in one tracking poll on Saturday but maintained a 9-to-10-point lead in others, has warned against complacency and urged Democratic supporters to vote.

"Don't believe for a second this election is over," the Illinois senator told a 15,000-strong crowd in Henderson, Nevada.

Speaking to supporters in Newport News, Virginia, McCain questioned Obama's readiness to lead in the face of such "grave threats" as al-Qaeda and the prospect of a nuclear-armed Iran.

He also attacked the Illinois senator's tax plans.

"He's running for redistributor-in-chief, I'm running for commander-in-chief," said McCain.

The final weekend has sprung a couple of surprises, one on each campaign so far.

On Saturday, it was revealed Palin, governor of Alaska, had been duped by a prank call in which a Canadian radio presenter successfully convinced her for five minutes that he was French President Nicolas Sarkozy.

Meanwhile, it was reported that a Kenyan aunt of Obama was living illegally in Boston four years after an immigration judge rejected her request for asylum.

Obama said he did not know the aunt, Zeituni Onyango, was in the country illegally, adding that the laws covering the situation should be followed.

President George W Bush, in his last weekly radio address before his successor is chosen, urged citizens to use their vote on 4 November.

Polling officials are expecting some 130 million Americans to vote, says the BBC's North America editor Justin Webb reports - a turnout which would be higher than in any election since 1960.