US campaign enters final weekend
John McCain attacked his rival over taxes in Virginia
The two men seeking to become president of the United States have entered the final weekend of campaigning before the 4 November election.
Democratic candidate Barack Obama still holds a poll lead, but one new survey suggests his lead over Republican John McCain is narrowing slightly.
Mr McCain is campaigning in Virginia and Pennsylvania before appearing on TV show Saturday Night Live.
Mr Obama is holding events in Nevada, Colorado and bellwether state Missouri.
Both men are visiting states seen as crucial to their chances of winning Tuesday's election.
Speaking to supporters in Newport News, Virginia, Senator McCain attacked his rival over the economy and his tax plans.
Referring to a comment by Mr Obama that he would "spread the wealth around", Mr McCain said: "He's running for redistributor-in-chief, I'm running for commander-in-chief."
ON THE CAMPAIGN TRAIL
There seems to be a two-pronged strategy: Sarah Palin energises the base, John McCain hangs out with his more centrist mates
After a lunchtime rally in Springfield, Virginia, Mr McCain will head to Perkasie, Pennsylvania, in the afternoon.
Analysts say Mr McCain needs to win in Pennsylvania - where he is behind in state polls - to have a chance.
Polls in Virginia, which has not backed a Democrat for president since 1964, show Mr Obama has pulled ahead of his rival there.
Mr Obama also has the edge over Mr McCain in Nevada and Colorado, both of which voted for George W Bush four years ago.
Missouri is seen as a vital state to win because of its record of backing the eventual winner in almost every election since 1904. Mr Obama leads in Missouri by a very narrow margin, polls show.
Mr Obama is extending his campaign advertising into traditionally Republican territory over the weekend, running advertisements in Arizona, his rival's home state, as well as Georgia and North Dakota.
As the candidates focus on battleground states, last-minute preparations are being made for Tuesday's vote, the BBC's North America editor Justin Webb reports.
Polling officials are expecting some 130 million Americans to vote - a turnout which would prove higher than in any election since 1960.
Security is of most concern in Chicago, Mr Obama's base, where up to one million people are expected to turn out in the city centre for what they hope will be a White House victory for the Illinois senator.
But Mr McCain is remaining defiant, playing on his status as the underdog and telling supporters on Friday night that he would still make a late run to victory.
He was boosted by the support of California Governor Arnold Schwarzenegger, who gave a rousing speech in the swing state of Ohio.
The ex-film star said Mr McCain was a real "action hero" who had spent more time as a prisoner of war than Barack Obama had served in the US Senate.
Although most worldly-wise Republicans expect to lose and most Democrats expect to win, both sides will be short of breath over the next few hours
North America editor Justin Webb
"We're closing, my friends, and we're going to win in Ohio," Mr McCain told the Ohio crowd.
"We're a few points down but we're coming back and we're coming back strong."
In a new poll Reuters/Zogby poll released on Saturday, Mr Obama's lead was down to five percentage points, at 49% to Mr McCain's 45%. The gap had narrowed from 7% in the previous survey.
Mr Obama warned supporters to expect a hard fight until the very end of the campaign.
"We are four days away from changing the United States of America," he said
Our correspondent says that while the McCain camp claim their candidate is just four points behind in the national polls, his problem is that in many states that he has to win, he is further behind.
No Republican has ever been elected without winning Ohio, Justin Webb adds, and John McCain appears to be five points adrift there at the moment.