 In times of extreme unrest, internal security actions may include measures such as internment (detention without trial).Depending on the nature of the specific state's form of government, enforcing internal security will generally not be carried out by a country's military forces, whose primary role is external defense, except in times of extreme unrest or other state of emergency, short of civil war.Often, military involvement in internal security is explicitly prohibited, or is restricted to authorized military aid to the civil power as part of the principle of civilian control of the military.