On Sunday, Horst Köhler visited Algerian Prime Minister Ahmed Ouyahia as part of a new UN initiative begun in April to mediate between the Algeria-backed Polisario Front and Morocco.

On Monday, he is due to complete his consultations in Mauritania.

Read more: Western Sahara's Moroccan-built wall

A UN-brokered ceasefire halted 16 years of insurgency in 1991, but the Polisario Front still wants a vote on self-determination in the arid, phosphate-rich region, which Morocco insists is a southern part of its kingdom.

Western Sahara, a former Spanish colony, covers 266,000 square kilometers (103,000 square miles) along the Atlantic coast, between Morocco and Mauritania, and has an estimated population of half a million.

Read more: Conflict in Western Sahara – The eternal wait

A 450-strong peacekeeping force, MINURSO, comprising mostly military observers, is based in Laayoune, the main city of Western Sahara.

Talks begin in Rabat

Köhler, 74, the former head of the International Monetary Fund (IMF) and Germany's ceremonial head of state between 2004 and 2010, is due to report back to the UN Security Council this coming week.

Last Monday and Tuesday, Köhler visited Moroccan leaders, including King Mohammed VI, before heading to Algeria's Tindouf region.

The area in southwestern Algeria has camps housing up to 200,000 refugees displaced from Western Sahara.

Arriving in Tindouf Wednesday, Köhler said he had come to "listen to both sides of the conflict, to see firsthand the conditions in the refugee camps and to better understand the issue and more importantly to form my personal vision."

Köhler, who began his new role as UN envoy in August, conceded that his task would be difficult: "I am not a magician."

Fresh impetus

The UN's decision to reopen negotiations, which foundered between 2007 and 2012, followed the resignation in March of the veteran American diplomat Christopher Ross. 

He ended his eight-year stint as UN envoy amid accusations by Rabat of bias in favor of the Polisario.

In January, Morocco was readmitted to the African Union after a 33-year absence prompted by the Western Sahara dispute.

The UN was also reportedly encouraged by a recent Polisario decision to pull back fighters from Guerguerat, a zone of tension on the border with Mauritania. 

To assert its territorial claims, Morocco has already built six mostly sand barriers along 2,700 kilometers of desert to cordon off the two-thirds of Western Sahara it annexed in 1975.

ipj/cmk (AFP, AP)