The United Nations Mission for the Referendum in Western Sahara (MINURSO) was established by Security Council resolution 690 of 29 April 1991 in accordance with settlement proposals accepted on 30 August 1988 by Morocco and the Frente Popular para la Liberación de Saguia el-Hamra y de Río de Oro (Frente POLISARIO).

The settlement plan, as approved by the Security Council, provided for a transitional period for the preparation of a referendum in which the people of Western Sahara would choose between independence and integration with Morocco.

The Special Representative of the Secretary-General was to have sole and exclusive responsibility over matters relating to the referendum and was to be assisted in his tasks by an integrated group of civilian, military and civilian police personnel, to be known as the United Nations Mission for the Referendum in Western Sahara.

MINURSO was originally mandated in accordance with the settlement plan to:

• monitor the ceasefire;
• verify the reduction of Moroccan troops in the Territory;
• monitor the confinement of Moroccan and Frente POLISARIO troops to designated locations;
• take steps with the parties to ensure the release of all Western Saharan political prisoners or detainees;
• oversee the exchange of prisoners of war, to be implemented by International Committee of the Red Cross, (ICRC);
• repatriate the refugees of Western Sahara, a task to be carried out by the United Nations High Commissioner for Refugees (UNHCR);
• identify and register qualified voters;
• organise and ensure a free and fair referendum and proclaim the results;
• reduce the threat of unexploded ordnances and mines.

While the organisation of the referendum has not been possible to date, other requirements of the mandate have been pursued successfully. MINURSO continues to perform the following tasks:

• Monitor the ceasefire;
• Reduce the threat of mines and UXOs;
• MINURSO provided logistic support to the UNHCR-led CBM (Confidence Building Measures) with personnel and air and ground assets and remain ready to continue supporting the UNHCR programme pending agreement of the two parties on a resumption of the activities, suspended in June 2014.

On an exceptional basis, MINURSO has been involved in providing assistance to irregular migrants as well as humanitarian help in case of natural disasters.