U.S. Immigration and Customs Enforcement was formed under the Homeland Security Act of 2002, following the events of September 11, 2001. With the establishment of the Department of Homeland Security, the functions and jurisdictions of several border and revenue enforcement agencies were combined and consolidated into U.S. Immigration and Customs Enforcement. Consequently, ICE is the largest investigative arm of the Department of Homeland Security and the second largest contributor to the FBI's Joint Terrorism Task Force.