US presidential candidates Barack Obama and John McCain plan to pull political adverts attacking one another on September 11.

Their decision came after the group MyGoodDeed.org asked them to perform good deeds on the day instead.

"Nine-eleven is not a day for politics," McCain spokesman Brian Rogers said.

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John McCain arrives in New Orleans earlier this week

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Barack Obama speaks at a town hall meeting in North Carolina this week

"We hope September 11th is a day when Americans come together and reaffirm our resolve to address the common challenges we face together," Obama spokesman Hari Sevugan said.

Both campaigns have been running tough ads against each other, with negative commercials outnumbering their positive spots.

MyGoodDeed.org is also among a number of organizations and families of September 11 victims who plan to hold a ServiceNation Summit on September 11-12 in New York. Sponsors invited Obama and McCain to attend a presidential candidates forum on September 11.

McCain has agreed to appear. Obama's campaign said it is talking with event sponsors about the possibility of an appearance.

In a letter to both candidates, MyGoodDeed.org founders David Paine and Jay Winuk noted that the country seemed to forget partisan differences in the days after the attacks and were unified by a sense of compassion.

"We ask you to help us rekindle that sense of unity by suspending your campaign activity on 9/11, and engaging in your own personal expression of charitable service in honor of those who perished and those who rose in service to help rebuild our nation," Paine and Winuk wrote to the candidates.

Paine, the president of the group, runs a marketing firm in California. Winuk's brother, Glenn Winuk, was a lawyer and volunteer firefighter who died after rushing to the World Trade Center to assist victims.

In an interview, Paine said: "We didn't feel that it was appropriate for those individuals who want to lead our country to engage in divisive political activity on 9/11.

Nine-eleven needs to be a day that is forever preserved as a day of unity and day of remembrance and day of compassion when we put aside our differences and we think about how we can help others in need."