Morocco's King Mohammed VI has ruled out any peace deal that allows for the independence of the Western Sahara as the United Nations renews efforts to resolve the decades-old dispute.

A U.N. peacekeeping force has been deployed in the former Spanish colony since 1991 with a mandate to organize a referendum on its independence or integration with Morocco. Morocco agreed to the vote in a 1988 agreement with the pro-independence Polisario Front that ended 13 years of conflict but has since blocked it being held, saying it will accept only autonomy for the territory.

"No settlement of the Sahara affair is possible outside the framework of the full sovereignty of Morocco over its Sahara and the autonomy initiative, whose seriousness and credibility the international community has recognized," the king said in a televised address on Monday.His speech marked 42 years since hundreds of thousands of Moroccan civilians marched across the border to lay claim to the mineral-rich territory. The "Green March" triggered war with the Algerian-backed Polisario Front which had been campaigning for independence for the territory since 1973.

Spread over 266,000 square kilometers (103,000 square miles) where the desert meets the Atlantic Ocean, the Western Sahara is the last territory on the African continent whose post-colonial status has yet to resolved. Morocco controls all of the territory's main towns. The Polisario controls parts of the desert interior.

The Sahrawi Arab Democratic Republic declared by the Polisario is a member of the African Union and recognized by many African governments. Morocco's claim to the territory is supported by the Arab League. The conflict has poisoned relations between Morocco and Algeria for decades. The land border between the North African neighbors has been closed since 1994.