France has backed Morocco's controversial autonomy plan for the disputed territory of Western Sahara.

In a letter addressed to Morocco's King Mohammed VI, French President Emmanuel Macron said a proposal to make Western Sahara an autonomous region of Morocco is the "only basis" to solve the long-running conflict.

"The present and future of Western Sahara fall within the framework of Moroccan sovereignty," Macron wrote in the letter that was made public on Tuesday.

"France intends to act consistently with this position at both national and international level."

The Polisario Front, which claims to represent the indigenous Saharawi population, insists that Western Sahara should be an independent country free from Moroccan control.

What is the Western Sahara conflict about?

Western Sahara was a Spanish colony in Africa until 1975.

After Spain withdrew, a war broke out between the Polisario Front and Morocco, which claimed the territory as its own. Tens of thousands of Saharawi refugees have for decades lived in camps across the border in Algeria due to the fighting.

In 1991, the United Nations began efforts to hold a referendum on the region's status. However, the process stalled due to disagreements over who should vote.

Most of the territory is currently controlled by Morocco, while a stretch of land in the east was declared as the Saharawi Arab Democratic Republic (SADR) by the Polisario Front. The UN says Western Sahara is a "non-self-governing territory."

"Whatever hardships Morocco tries to impose on us with the support of France, the Sahrawi people will continue to stubbornly defend their rights until they obtain the definitive departure of the Moroccan aggressor from their territory and general recognition of the legitimacy of their struggle for self-determination and independence," the SADR's Foreign Minister Mohamed Sidati said on Monday.

Morocco's diplomatic push

France's announcement that it would change its decades-long position on the status of Western Sahara is a major victory for Morocco.

The Moroccan Royal Palace said the announcement was a "significant development in support of Moroccan sovereignty over the Sahara."

France joins the United States, Israel, Spain and a growing number of African countries that have in recent years backed Rabat's position as Morocco seeks to deepen trade ties. Western Sahara is home to some of the world's largest phosphate reserves. 

However, the move was condemned by Algeria — Morocco's regional foe and a supporter of the Polisario Front.

France had long attempted to walk a fine line between Morocco and Algeria on the matter. Algeria said France alerted it about the change in policy last week.

"The French decision is clearly the result of a dubious political calculation, a morally questionable judgment and legal interpretations that are neither supported nor justified," the Algerian Foreign Ministry said in a statement.

zc/rc (Reuters, AFP, AP)