The Central Intelligence Agency reports that at least ten countries are believed to possess or be conducting research on biological agents for weaponization. In the United States, most terrorist incidents have involved small extremist groups who use terrorism to achieve a designated objective. Local, State and Federal law enforcement officials monitor suspected terrorist groups and try to prevent or protect against a suspected attack. Additionally, the U.S. government works with other countries to limit the sources of support for terrorism. A terrorist attack can take several forms, depending on the technological means available to the terrorist, the nature of the political issue motivating the attack, and the points of weakness of the terrorist's target.
Bombings are the most frequently used terrorist method in the United States.
Other possibilities includes an attack at transportation facilities, an attack against utilities or other public services or an incident involving chemical or biological agents. Terrorist incidents in this country have included bombings of the World Trade Center in New York City, the United States Capitol Building in Washington, D.C. and Mobil Oil corporate headquarters in New York City.