Islamic extremism in the United States comprises all forms of Islamic extremism occurring within the United States. Islamic extremism is an adherence to a fundamentalist interpretation of Islam, potentially including the promotion of violence to achieve political goals. In the aftermath of the September 11, 2001 terror attacks, Islamic extremism became a prioritized national security concern of the U.S. government and a focus of many subsidiary security and law enforcement entities. Initially, the focus of concern was on foreign Islamic terrorist organizations, particularly al-Qaeda, but in the course of the years since the September 11 terror attacks, the focus has shifted more towards Islamic extremist and Jihadist networks within the United States. Although the number of U.S. citizens o