The 35-year-old United Nations (UN) peacekeeping mission in the Western Sahara region will come to an end after the Security Council failed to renew its mandate, the UN ​chief said on Sunday.

Morocco, which claims the Western Sahara as its ‌own, welcomed the decision, while its opponents in the Algeria-backed Polisario Front expressed concern.

The Polisario Front has been seeking an independent state in Western Sahara since former colonial power Spain left ​in 1976.

A peacekeeping mission, known as MINURSO, has been in place there ​since a UN-brokered ceasefire in 1991.

November 1 would mark the start ⁠of the “liquidation phase” of the mission, with assets transported back to troop-contributing countries, ​UN chief Antonio Guterres said in a statement.

The end of the peacekeeping mission comes ​a year after the UN Security Council adopted a US-drafted resolution that accepted Rabat’s plan to give the territory autonomy under Moroccan sovereignty as the “most feasible” solution to the conflict.

Russia, which abstained ​in last year’s vote, this year vetoed another US-backed resolution that would have ​cemented the UN’s preference for the Moroccan plan while scaling back the peacekeeping force.

The Security Council ‌then ⁠defeated a competing Russian resolution, leaving the mission to expire without a new mandate.

Besides monitoring the ceasefire, MINURSO was tasked with organizing a referendum that has never taken place due to disagreements over voter eligibility.

Morocco’s Foreign Minister Nasser Bourita told state ​media that the ​mission’s reference to ⁠a referendum – the “R” in its name – was an “anachronism”.

Rabat had been informed that Russia was going to block the US-drafted resolution, but ​saw it as “an opportunity to review certain rules of the ​game”, he ⁠said.

Morocco’s royal palace had said the non-renewal of the mission was a “significant development” towards withdrawing the Western Sahara issue from consideration by the Security Council.

Algeria’s Foreign Ministry on ⁠Saturday expressed “deep ​regret” over the non-renewal, blaming the “excessive bias” of ​the US towards Morocco’s position.