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The Movement for the Liberation of the Saguia el Hamra and Rio de Oro, sometimes referred to as the Movement for the Liberation of the Sahara or simply the Liberation Movement (Harakat Tahrir in Arabic) was created in 1969 by Muhammad Bassiri, a Smara-based Sahrawi quranic teacher, to work for the independence of Western Sahara.

The aim of the Harakat Tahrir was the peaceful overturning of Spanish colonial rule and achievement of then-Spanish Sahara's self determination. It initially organized and operated in secret, but revealed its existence in a demonstration in El-Aaiun against Spanish rule on June 17, 1970, when it attempted to hand over a petition to the Spanish colonial rulers calling for better treatment and Western Sahara's independence.

The protest was bloodily suppressed by the occupation forces. The massacre and ensuing disturbances has been named the Zemla Intifada, or uprising, after the place the demonstration was held. A nation-wide hunt for members of the movement followed: Bassiri himself was arrested and "disappeared" in Spanish custody. He is assumed to have been killed by his jailors, and is counted by the present-day Sahrawi nationalist movement as its first modern-day martyr.

After the crushing of the Harakat Tahrir, Sahrawi nationalists abandoned the hope of a peaceful end to colonial occupation. In May 1973 the militant Front Polisario formed under the leadership of El-Ouali, calling for armed revolution against Spanish rule. The Polisario, which is still active, would later turn its guns on the Moroccan and Mauritanian forces which invaded Western Sahara upon Spain's departure in 1975.