Swedish Military Intelligence and Security Service

Military Intelligence and Security Service (Swedish: Militära underrättelse- och säkerhetstjänsten, MUST) is a division of the Swedish Armed Forces Central Command.

MUST is both a foreign intelligence and a military security/counterintelligence agency. In its intelligence role, MUST is responsible for providing intelligence on foreign threats to the Government of Sweden and the Swedish Armed Forces. However, signals intelligence is handled by a separate civilian agency operated by the Ministry of Defence, the Swedish National Defence Radio Establishment (FRA), which is not part of MUST.

MUST is legally prohibited from gathering intelligence on Swedish domestic affairs, except in its more narrowly defined role a counter-intelligence agency tasked with identifying threats to the armed forces, such as sabotage, espionage, or infiltration. Domestic security and civilian counterintelligence in non-military contexts are handled by the Swedish Security Service (SÄPO), the civilian equivalent agency to MUST.