UN Secretary-General Spokesperson, Stéphane Dujarric, has said that the United Nations Mission for the Referendum in Western Sahara (MINURSO) had not witnessed any movements made by military combatants in the north-eastern region. He added that the mission is closely watching the situation.
Dujarric's statement came in response to a letter sent by the Permanent Representative of Morocco to the United Nations, Omar Hilal, to UN Security Council President Gustavo Meza-Cuadrain.
Morocco warned that the Polisario's establishment of any civil, military, administrative structure from Tindouf camps in Algeria to the east of the security wall of the Sahara constitutes a provocative act that might lead to war.
Hilal said that with its repeated violations, which are now extending to several areas in the east of the security wall in the Moroccan Sahara, the Polisario is seriously threatening the other parties, leaving no possible opportunity to re-launch the political process.
Earlier, Moroccan Prime Minister Saad Eddin Al-Othmani said that his country did not and will not allow any changes to the facts on the ground in the buffer zone, particularly the construction of buildings.
On Sunday Moroccan authorities announced that they had notified the UN Security Council about the Polisario Front's incursions, describing such acts as extremely dangerous in the buffer zone in Western Sahara.
Watch: Western Sahara explainer
Moroccan Minister of Foreign Affairs Nasser Bourita said: "There are provocations and manoeuvres. Algeria is encouraging the Polisario to change the situation of this buffer zone, which has been placed under the United Nations' responsibility since the early 1990s."
In a meeting of the parliament's foreign affairs committees in the presence of political party leaders, he added: "If the United Nations is not ready to put an end to these provocations, Morocco will assume its responsibilities and will not tolerate any change that could happen in this region."
Bourita called on the United Nations and the sovereign powers to bear their responsibility. He stressed that if the United Nations and the Security Council cannot protect the region, Morocco will certainly assume its responsibility.
The Polisario has criticised the Moroccan statements and considered them as an "attempt to disavow the peace process". The Front's coordinator with the UN, Mohammed Khaddad, told Agence France Presse: "We condemn this disavowal, and we will respond to any breach of the ceasefire agreement."
The dispute over the Sahara between Morocco and the Polisario started in 1975 and the ceasefire agreement was signed in 1991. The United Nations deployed its mission known as MINURSO and launched negotiations between the two sides in search of a final solution to the dispute over the region.
On 24 March 2018 The UN Security Council urged the UN special envoy to Western Sahara Horst Köhler to relaunch negotiations to resolve the dispute.