Western Sahara - North Africa’s disputed thorn

Western Sahara is a former Spanish colony that is mostly under Morocco’s control but is claimed by an Algerian-backed independence movement which has campaigned for a vote on self-determination through decades of war and deadlock.

Here is some background on the sprawling, desert territory -- the only one on the African continent whose post-colonial status has yet to be resolved -- as the United Nations prepares to convene new talks in Geneva on Wednesday.

- Between desert and ocean - The north African territory sits on the western edge of the vast Sahara desert, stretching along about 1,000 kilometres (620 miles) of Atlantic coastline.

At 266,000 square kilometres (103,000 square miles) it is relatively large but its inhospitable terrain supports only around half a million people.

Bordering Morocco to the north, Algeria to the east and Mauritania to the south and southeast, it boasts large reserves of phosphate and rich offshore fisheries.

Its largest city is Laayoune, which is administered by Morocco and where about 40 percent of its population lives.

As Spain withdrew in 1975, Morocco moved in, claiming that the territory was an integral part of the kingdom.

It was opposed by the Polisario Front, which took up arms to fight for independence.

The dispute was referred to the International Court of Justice in The Hague which ruled in favour of self-determination.

In November 1975, 350,000 Moroccans, took part in the so-called Green March to the border to press the kingdom’s claim.

In February 1976, the Polisario Front proclaimed the Sahrawi Arab Democratic Republic (SADR), with the support of allies including Algeria and Cuba.

- Separated by sand wall - The Polisario initially gained the upper hand before being pushed back into the interior.

During the 1980s, Morocco built a series of concentric walls in the desert, most made of sand, to keep Polisario fighters out of territory where it had established control.

The outermost defensive line runs for 2,700 kilometres across the desert, ringing the 80 percent of the Western Sahara now under Moroccan control.

It is fortified with barbed wire and trenches and forms one of the world’s largest minefields.

A Un-brokered ceasefire in 1991 perpetuated the line of control.

The SADR is a member of the African Union but controls just 20 percent of its territory, mostly empty desert.

Morocco rejoined the African bloc last year after a 33-year absence under the cloud of the dispute.

The conflict has long poisoned its relations with neighbouring Algeria.