The Federal Bureau of Investigation (FBI) categorizes terrorism in the United States as one of two types -- domestic terrorism or international terrorism.
- Domestic terrorism involves groups or individuals whose terrorist activities are directed at elements of our government or population without foreign direction.
- For example, Ted Kaczynski's mail bomb attacks on universities as the "Unabomber" were acts of domestic terrorism.
- International terrorism involves groups or individuals whose terrorist activities are foreign-based and/or directed by countries or groups outside the United States or whose activities transcend national boundaries.
- The September 11, 2001 attacks on the World Trade Center and the Pentagon were acts of international terrorism.
