The UN chief on Friday urged Morocco and the Polisario Front to accept his next candidate for the post of UN special envoy for the disputed region of Western Sahara, after they rejected all the previous candidates.
The Polisario Front has for decades fought Morocco for the independence of Western Sahara, a desert region bigger than Britain which was a Spanish colony until 1975.
"It is absolutely essential to have an envoy to relaunch the political dialogue on Western Sahara," UN Secretary-General Antonio Guterres said at a joint press conference in Madrid with Spanish Prime Minister Pedro Sanchez.
"The difficulty is that we already put forward 13 names, and until now, we haven't got the parties' agreement, which is very important... because the envoy has to work with them to launch the political dialogue."
Relaunching dialogue over the long-running conflict was also critical "for facing up to existing frustrations because of a crisis which still has no way out," he said.
Although Guterres did not identify the latest candidate, it was, according to diplomatic sources at the UN, former UN special envoy for Syria Staffan de Mistura. The same sources said his name was accepted by the Polisario, but turned down by Morocco.
US Secretary of State Antony Blinken had in March urged Guterres to speed up the process of appointing a new special envoy for Western Sahara to fill what was then a nearly two-year vacancy.
The position has been vacant since May 2019, when former German president Horst Kohler stepped down, officially for health reasons.
Morocco controls 80 percent of Western Sahara, while the rest -- an area bordering Mauritania that is almost totally landlocked -- is run by the Polisario Front and known as the Sahrawi Arab Democratic Republic.
Rabat has offered the vast territory autonomy but maintains it is part of the Moroccan kingdom.
After 16 years of war, Rabat and the Polisario signed a ceasefire in 1991, but a UN-backed referendum on self-determination has been constantly postponed.
Western Sahara is designated by the UN as a "non-self-governing territory" whose people "have not yet attained a full measure of self-government".
Hostilities resumed in November when the Polisario, which is backed by Algeria, declared the ceasefire over after Morocco sent troops into a UN-patrolled buffer zone to reopen a key road.