The population of the Western Sahara engaged in two prolonged struggles for independence, first from Spain (1973-1975) and then from Morocco (1976-1991). The Fenete Popular para la Liberaçion de Saguia el-Mamr y del Rio de Oro (POLISARIO) waged a war against the Moroccan troops that occupied the Western Sahara in 1975. The United Nations (UN) intervened with a peace plan that included a ceasefire and a referendum on independence. It also established the United Nations Mission for the Referendum in Western Sahara (Spanish acronym: MINURSO). The Canadian contingent included 34 military observers. The Canadian government withdrew the Canadian contingent in 1994 due to difficulties in establishing a ceasefire.