Because of both the secrecy of secret services and the controversial nature of the issues involved, there is some difficulty in separating the definitions of secret service,secret police,intelligence agency etc. For instance a country may establish a secret service which has some policing powers (such as surveillance) but not others. A secret police may also be said to be a secret service. The powers and duties of a government organization may be partly secret and partly not. The organization may be said to operate openly at home and secretly abroad, or vice versa.
