NEW YORK, Sept 10: Americans will pay quiet tribute on Saturday to victims of the Sept 11 terror strikes, amid a presidential election war of words over national security.

A taunting reminder of the traumatic events of three years ago came Thursday in the form of a video statement by Al Qaeda number two Ayman al-Zawahiri.

Osama bin Laden's deputy said defeat for US forces in Iraq and Afghanistan was just a matter of time and warned that Americans would not be safe while their government "commits crimes against Muslims in Iraq and Afghanistan and Palestine."

With the Nov 2 presidential election looming, the video tape triggered fresh debate between Republicans and Democrats over President George W. Bush's national security strategy in the wake of the Sept 11 attacks.

Three years after jets hijacked by Al Qaeda members devastated the World Trade Center towers, fear of fresh terrorist strikes remains a potent force among Americans, fuelled in the past week by images of the terrorist bombing in Jakarta and massacre of schoolchildren in Beslan, Russia. And the third anniversary comes just days after the death toll of US soldiers in Iraq crossed the symbolic 1,000 mark - a grim reminder of the cost of the open-ended war on terror.

For Bush, Sept 11 remains the defining moment of his presidency and the foundation of his national security policy, which he has placed at the centre of his election campaign.

While Kerry has focused more on economic and health issues, he has also struggled to present himself as a more effective commander-in-chief who would keep Americans safe.

As was the case with the past two anniversaries, New York City will be the focus of Saturday's remembrance events, with a ceremony at Ground Zero featuring parents and grandparents reading the names of the 2,749 victims of the World Trade Center attack. The reading will pause at four moments: twice to mark the times that each plane hit the towers and twice more to mark the times each tower fell. -AFP