Security agency

The distinction, or overlap, between security agencies, national police, and gendarmerie organizations varies by country.

In the United States, the FBI and CIA are civilian agencies, although they have various paramilitary traits and have professional relationships with the U.S.'s military intelligence organizations.

In many countries all intelligence efforts answer to the military, whether by official design or at least on a de facto basis.

In Ireland, for example, intelligence operations relevant to internal security are conducted by the military (G2) and police (SDU), rather than civilian agencies.

Security agencies are constrained in some countries by a mesh of judicial and legislative accountability, whereas in others they may answer only to a single leader or executive committee.