Terrorist attacks are often targeted to maximize fear and publicity, usually using explosives or poison.[168] Terrorist groups usually methodically plan attacks in advance, and may train participants, plant undercover agents, and raise money from supporters or through organized crime. Communications occur through modern telecommunications, or through old-fashioned methods such as couriers. There is concern about terrorist attacks employing weapons of mass destruction.
Terrorism is a form of asymmetric warfare, and is more common when direct conventional warfare will not be effective because opposing forces vary greatly in power.[169]
The context in which terrorist tactics are used is often a large-scale, unresolved political conflict. The type of conflict varies widely; historical examples include:
Secession of a territory to form a new sovereign state or become part of a different state
Dominance of territory or resources by various ethnic groups
Imposition of a particular form of government
Economic deprivation of a population
Opposition to a domestic government or occupying army
Religious fanaticis