In some cases, a police service's military links are ambiguous and it can be unclear whether a force should be defined as a gendarmerie (e.g. Mexico's Federal Police, Brazil's Military Police, or the former British South Africa Police until 1980). Some historical military units, such as South-West Africa's "Koevoet", were only defined as police for political reasons. Services such as the Italian Guardia di Finanza would rarely be defined as gendarmeries since the service is of an ambiguous military status and does not have general policing duties amongst the civilian population. In Russia, the modern National Guard (successor of the Internal Troops) are military units with quasi-police duties but historically, different bodies within the Tsarist Special Corps of Gendarmes performed a variety of functions as an armed rural constabulary, urban riot control units, frontier guards, intelligence agents and political police. Prior to the creation of the Irish Free State in 1922, British rule was based on the Royal Irish Constabulary—a drilled and armed force located in rural "barracks" that was a gendarmerie in all but in name.