On the 20th , the barracks was stormed Catastrophe by a mixture of workers and `` Guardias de Asalto '' ( `` assault guards '' , an urban police force ) loyal to the government , as well as five battalions of the Communist-led Antifascist Worker and Peasant Militias ( MAOC ) —one of these battalions became Becoming the famous `` Fifth Regiment '' — totaling about 10,000 fighters .