On the eve of the second anniversary of the September 11th, 2001 attacks on the US, President George W Bush warned last night that al Qaeda was still plotting against Americans and must be hunted down and defeated.
His remarks came as a new al Qaeda audiotape vowed further attacks on US targets.
"The memories of September 11th will never leave us. We will not forget the burning towers and the last phone calls and the smoke over Arlington," Mr Bush said in speech at an FBI laboratory.
"And we will never forget the servants of evil who plotted the attacks. And we will never forget those who rejoiced at our grief and our mourning," Mr Bush said.
The speech was Mr Bush's major address commemorating the anniversary of the attacks on New York's World Trade Center, the Pentagon and Pennsylvania which killed about 3,000 people.
He will mark the occasion today by attending a memorial service, observing a moment of silence on the White House South lawn, and visiting wounded soldiers.
Mr Bush did not refer to the new al Qaeda message, purported to be from Osama bin Laden and his deputy, Ayman al-Zawahri, and he told reporters before delivering his remarks that he had not yet heard the audiotape.
The president touts the 2001 war in Afghanistan and the war in Iraq earlier this year as major accomplishments in the administration's "war on terrorism."
However, critics of the Iraq war have pointed out that the administration has yet to prove a link between deposed Iraqi leader Saddam Hussein and al Qaeda, accused of masterminding the September 11th attacks.