Spies can be used to gather intelligence on field armies, infiltrate foreign cities to identify enemy installations, and serve in a counter-espionage role in the players own cities.
The bureau was split into naval and army sections which, over time, specialised in foreign espionage and internal counter-espionage activities respectively.
Such operations should not include armed conflict by recognized military forces, espionage, counter-espionage, and cover and deception for military operations.