Democratic presidential candidates have rebuked Republican rival Rudy Giuliani for suggesting that the United States could face another major terrorist attack if a Democrat is elected in 2008.
Barack Obama said Mr Giuliani, who was in office on September 11, 2001, should not be making the terrorist threat into "the punchline of another political attack.
"Rudy Giuliani today has taken the politics of fear to a new low, and I believe Americans are ready to reject those kind of politics," Mr Obama said in a statement.
John Edwards said the former New York mayor knows better than to suggest there is a "superior Republican way to fight terrorism."
Senator Hillary Rodham Clinton said protecting the country from terrorism "shouldn't be a political football," adding: "It should be a solemn responsibility that all of us pledge to fulfill regardless of what party we're in."
But Mr Giuliani stood by his comments, saying Democrats don't understand the threat posed by terrorists.
"They do not seem to get the fact that there are people, terrorists in this world, really dangerous people that want to come here and kill us," Mr Giuliani said on The Sean Hannity Show, according to a transcript distributed by his campaign. "They want to take us back to not being as alert which to me will just extend this war much, much longer."
The former mayor had said if a Democrat is elected, "it sounds to me like we're going on defense. We're going to wave the white flag there."
But, he said, if a Republican wins, "we will remain on offense" trying to anticipate what the terrorists are going to do and "trying to stop them before they do it".