President George W. Bush and Secretary of State Condoleezza Rice expressed concern Thursday that the commitment of NATO allies in Afghanistan may be flagging and warned against allowing the country to again become a cauldron for extremism. In separate news conferences, Bush and Rice made clear that the United States cannot accept Afghanistan as a failed state where al-Qaida is able to regroup and possibly use as a stage to launch future terrorist strikes like the Sept. 11, 2001, attacks. "My biggest concern is that people say, 'Well, we're kind of tired of Afghanistan and, therefore, we think we're going to leave'," Bush said at the White House. "That would be my biggest concern." Later, Rice made the same point at a joint news conference at the State Department with Canadian Foreign Minister Maxime Bernier. The Canadian government and parliament will begin debate early next year on whether to extend Canada's military operations in Afghanistan beyond its current mandate that ends in February 2009.