Two senior Bush administration officials this week offered differing assessments of al-Qaeda's capability to carry out a major new attack against the United States.

The terrorist network continues to pose a serious threat to the United States, potentially involving the use of weapons of mass destruction, according to a key White House adviser.

Kenneth Wainstein, homeland security adviser to President George W. Bush, said Wednesday that the United States succeeded in weakening al-Qaeda shortly after the Sept. 11, 2001, terrorist attacks. Washington and its allies quickly expelled al-Qaeda and its Taliban hosts from Afghanistan, and since then have targeted high-ranking operatives and their financial networks throughout the region and around the globe.