Sarandon is a well-known campaigner

The United Way group in Tampa Bay, Florida, had invited the actress, who has spoken out against the war in Iraq, to an event on women and volunteering to be held on 11 April.

But the group, which promotes community action and volunteering schemes, had begun to receive complaints about her involvement.

United Way of Tampa Bay chairwoman Robin Carson said the event had the potential to become "divisive".

"The focus of our whole meeting had shifted to whether or not we were creating a political platform for Susan Sarandon," she said.

"That is not our purpose. That's not what we're about."

A statement from the group added: "We have enormous respect for the diversity of ideas and the principles of free speech, but United Way of Tampa Bay's intent is to unify the diversity of thought that brings the community together."

Together with husband Tim Robbins, Sarandon has been one of the United States' leading voices against military action in Iraq.

Last month she shared a platform with South Africa's Archbishop Desmond Tutu at a 100,000-strong anti-war rally in New York.

She was an award presenter at the Oscars on Sunday, where she gave a peace sign to the audience but did not speak out against the war.