The Spanish enclave of Ifni in the south was returned to Morocco in 1969. The Polisario movement was formed in 1973, with the aim of establishing an independent state in the Spanish Sahara. On 6 November 1975 King Hassan asked for volunteers to cross into the Spanish Sahara. Some 350,000 civilians were reported as being involved in the "Green March". A month later, Spain agreed to leave the Spanish Sahara, soon to become Western Sahara, and to transfer it to joint Moroccan-Mauritanian control, despite the objections and threats of military intervention by Algeria. Moroccan forces occupied the territory.