Senators John McCain and Barack Obama say they will put aside partisan politics for a joint appearance at ground zero in New York to mark the seventh anniversary of the September 11 attacks.
The Democratic and Republican presidential nominees, in a statement on Saturday, said they will appear together at the World Trade Centre site on Thursday "to honour the memory of each and every American who died" in the 2001 attacks.
The campaigns had already agreed to suspend television advertising critical of each other on September 11. The McCain campaign has said it will air no ads that day.
Both campaigns have been running negative television ads and, at the just-concluded political conventions, pulled no punches in exploiting partisan differences.
Obama and McCain said Thursday will be different.
"All of us came together on 9/11 - not as Democrats or Republicans - but as Americans," they said. "We were united as one American family. On Thursday, we will put aside politics and come together to renew that unity."
A group backing community service, MyGoodDeed.org, wants September 11 to become a national day of voluntary service and had asked that Obama and McCain perform acts of community service instead of campaigning.
Nearly 3,000 people were killed after hijackers rammed passenger planes into the Twin Towers in New York and the Pentagon. The death toll includes 40 passengers and crew members aboard the fourth hijacked plane, United 93. It crashed in a field near Shanksville, Pennsylvania, as passengers rushed the cockpit, investigators believe.
