The Assault Guards were special police units created by the Spanish Republic in 1931 to deal with urban violence.
At the start of the Spanish Civil War there were 18,000 Assault Guards. About 12,000 stayed loyal to the Popular Front government, while another 5,000 joined the Nationalists.
The Assault Guards helped to put down the Nationalist uprising in June 1936. They were also used against the Anarcho-Syndicalists and the Worker's Party (POUM) in Barcelona in May 1937.