Classification of Intelligence Services According to Their Main Area of Interest
Intelligence services can also be classified according to "the main area of their interest" into solely military services and civil intelligence services. Military services focuses (in terms of defensive or intelligence activity) on military affairs, defensibility, defence industry and various aspects of the military (the number, structure, preparedness, location and armament). The misleading but often used term "civil" means that these services focus on wide variety of political, security and economic issues, i.e. all except from the military ones. Thus in the imaginary pie chart the activity of the civil services would cover much bigger part than the activity of military services.
This statement brings us to another possible criterion: intelligence services can be classified into 1) "national", focusing on national security issues, problems of survival or prosperity of the state as a whole, and 2) departmental ones. The latter are either established for specific purposes (for instance tracing illegal flows of money) or serve as support and a provider of news and intelligence for the operation of its department. Military intelligence services belong among the latter type of services. They are an integral and essential part of the armed forces of their country; their mission, especially at the tactical and operational level, is the immediate support for combat operations and other operations; they are integrated into the complex of related activities. This is one of the reasons why aside from the main military intelligence service, some countries have separated "subordinate" intelligence services of individual military forces (the army, the air force, the navy).
Source: Petr Zeman - lectures, trainings and public speeches