In the early 20th century, the popularity of socialism and anarchism grew throughout Spain. There was widespread discontent in Catalonia, which was heavily industrialized and was a stronghold of the anarcho-syndicalist trade unions. A series of strikes due to wage cuts and in response to military conscription for the Second Rif War in Morocco culminated in the Tragic Week (25 July – 2 August 1909) in which workers rose up in revolt and were suppressed by the army. The anarcho-syndicalist Confederación Nacional del Trabajo (CNT) was formed in October 1910 and immediately called for a general strike, which was suppressed by the military. Further strikes followed in 1917 and 1919 amidst growing violence between the police and trade unions. With the CNT outlawed, the Federación Anarquista Ibérica (FAI) was formed in 1927 as a clandestine alliance of affinity groups during the dictatorship of Miguel Primo de Rivera. Its radical members, who were also part of the CNT, exerted considerable influence on the other members of the trade union. During the Second Spanish Republic, anarchists continued to lead uprisings such as the Casas Viejas revolt in 1933 and the Asturian miners' strike of 1934 which was brutally put down by Francisco Franco with the aid of Moorish troops.