WASHINGTON, 4 March 2005 — In a rare mention of the mastermind of the Sept. 11 attacks, President George W. Bush said yesterday stopping Osama Bin Laden from a new attack on American soil was “the greatest challenge of our day” and vowed to hunt down the Al-Qaeda leader.

Bush said recent reports that Bin Laden had asked his chief ally in Iraq, Abu Musab Al-Zarqawi, to plan attacks in the United States was a warning that Al-Qaeda was still a threat to Americans at home.

“Recently we learned that Osama Bin Laden has urged the terrorist Zarqawi to form a group to conduct attacks outside Iraq, including here in the United States,” Bush said at a public ceremony swearing in of Michael Chertoff as the new head of the US Homeland Security Department.

“Bin Laden’s message is a telling reminder that Al-Qaeda still hopes to attack us on our own soil. Stopping him is the greatest challenge of our day,” he added.

Bush said that as the United States shifted its defenses to counter the threat from Al-Qaeda, “the terrorists will adapt their tactics in response.”

“We’re on a constant hunt for Bin Laden. We’re keeping the pressure on him, keeping him in hiding,” he said.