In the closing years of the nineteenth century, labor organizations gathered force, first as mutual aid societies and then increasingly as trade unions. In the opening decades of the twentieth century, labor organizing, unrest, and strikes reached new levels of intensity. In the northern nitrate and copper mines, as well as in the ports and cities, workers came together to press demands for better wages and working conditions. Attracted strongly to anarchist, anarcho-syndicalist, and socialist ideologies, they were harshly repressed during the Parliamentary Republic. The government carried out several massacres of miners in the nitrate camps; the most notorious took place in Iquique in 1907. Thus, a pattern of violent clashes between soldiers and workers took shape.