George W Bush and John Kerry are campaigning furiously in the final days before Tuesday's US presidential vote.
President Bush, flanked by Air Force One, in New Hampshire on Friday
The candidates are targeting a handful of battleground states in an effort to secure vital swing votes as polls put them neck-and-neck.
On Friday, they were in New Hampshire, Florida and Ohio. Between them the candidates will speak at seven rallies in six key states on Saturday.
Arnold Schwarzenegger lent his support to President Bush in a rally on Friday.
At the rally in Columbus, Ohio, Mr Schwarzenegger again punned on his bodybuilding, Hollywood background as he put his weight behind Mr Bush.
"I'm here to pump you up to re-elect President George W Bush," he told screaming Republicans.
"Now is the time to flex your muscles for bold leadership, for a strong economy. If you flex your muscles November 2nd, I guarantee you President Bush will be back."
Rock star Bruce Springsteen appeared on stage with Mr Kerry on Thursday, and is set to join him again on Monday.
The focus of campaigning on Friday returned to terrorism and national security, as each candidate tried to sell himself as the best man to protect the US from attack.
Speaking to a rally in Manchester, New Hampshire - a small state worth just four electoral college votes - President Bush was joined on stage by relatives of victims of the 11 September 2001 attacks.
"As long as I am the president, we will be determined and steadfast and we will keep the terrorists on the run," he said.
In West Palm Beach, Florida, Mr Kerry addressed about 2,000 people amid a continuing controversy between Republicans and Democrats over voter registration and plans to monitor polling stations on election day.
The challenger revisited familiar themes, attacking President Bush's record on national security and claiming Americans needed a "fresh start".
He criticised the costs of war in Iraq and accused the president of allowing Osama Bin Laden to escape from the mountains of Afghanistan.
Controversy over what happened to a huge explosives cache in Iraq, and a new videotape of Bin Laden, have placed extra pressure on both candidates to score points.
The candidates continue to jostle for the lead in opinion polls.
A Reuters/Zogby tracking poll the candidates in a dead heat at 47% each nationally. Other polls show the candidates as tied or give Mr Bush a slim lead.
On Saturday, Mr Bush will leave Ohio for the states of Michigan, Wisconsin, Minnesota, and Florida.
KEY SWING STATES
1. Florida - 27 electoral votes
2. Pennsylvania - 21
3. Ohio - 20
4. Minnesota - 10
5. Wisconsin - 10
6. Iowa - 7
7. Nevada - 5
8. New Mexico - 5
9. New Hampshire - 4
Mr Kerry will concentrate his efforts on Wisconsin and Ohio.
With the race so close, the candidates are trying to win every electoral college vote they can. The victor will need at least 270 votes.
Vice-President Dick Cheney announced plans to visit Hawaii over the weekend, in a play for the four electoral votes, as polls there showed a tight race in what is traditionally a Democrat bastion.
Mr Kerry's daughter Alexandra will visit over the weekend in a counter-bid for votes.