"President Bush signed Executive Order 13224 on September 23, 2001. Executive Order 13224 gives the U.S. Government a powerful tool to impede terrorist funding and is part of our national commitment to lead the international effort to bring a halt to the evil of terrorist activity. President Bush issued Executive Order 13224 pursuant to the authorities of the International Emergency Economic Powers Act (50 U.S.C. 1701 et seq.)(IEEPA), the National Emergencies Act (50 U.S.C. 1601 et seq.), section 5 of the United Nations Participation Act of 1945, as amended (22 U.S.C. 287c)(UNPA), and section 301 of title 3, United States Code. In issuing Executive Order 13224, President Bush declared a national emergency to deal with the unusual and extraordinary threat to the national security, foreign policy, and economy of the United States posed by grave acts of terrorism and threats of terrorism committed by foreign terrorists, including the terrorist attacks in New York and Pennsylvania, and on the Pentagon committed on September 11, 2001, and the continuing and immediate threat of further attacks on U.S. nationals or the United States. In general terms, the Order provides a means by which to disrupt the financial support network for terrorists and terrorist organizations by authorizing the U.S. government to designate and block the assets of foreign individuals and entities that commit, or pose a significant risk of committing, acts of terrorism."
United States. Dept. of State: http://www.state.gov/