President George W. Bush has insisted the US will not be intimidated by al-Qaeda.
He was reacting to the release of a videotape of Osama bin Laden, in which he derided Mr Bush and warned of possible new September 11th-style attacks.
Bin Laden, making his clearest claim yet of responsibility for the strikes of 2001, said Mr Bush had failed Americans with his Middle East policies, deceiving the nation and putting it at risk from further al-Qaeda strikes.
He said the September 11 attacks would not have been so severe if Bush had been alert.
Mr Bush vowed that "Americans will not be intimidated or influenced" by the video.
Election challenger Mr John Kerry, who has criticized Mr Bush for failing to capture bin Laden by diverting troops to Iraq, called bin Laden a barbarian. "I will stop at absolutely nothing to hunt down and capture or kill the terrorists wherever they are, whatever it takes," he said, running neck and neck with Mr Bush in opinion polls.
In what seemed a deliberate attempt to influence Tuesday's US election, bin Laden used the opening line: "O American people, I am speaking to tell you about the ideal way to avoid another Manhattan, about war and its causes and results."
But he made little mention of Mr Kerry, saying: "Your security is not in the hands of Kerry or Bush or al-Qaeda. Your security is in your own hands and each state which does not harm our security will remain safe."