ALGIERS - Morocco has informed Algeria through diplomatic channels that it will intervene militarily in Western Sahara if Sahrawi forces do not withdraw from the area east of the defensive wall, an Algerian diplomatic source told Middle East Eye.

According to the source, Rabat used the ambassador of a European country as an intermediary in Algiers to deliver the message.

On 1 April, Morocco alerted the UN Security Council following incursions by the Polisario Front into the northeastern Western Sahara town of Mahbes, in violation of the 1991 military agreement setting up a buffer zone.

This week, Moroccan Foreign Minister Nasser Bourita handed a letter from King Mohammed VI to UN Secretary General Antonio Guterres, expressing "the firm and determined rejection of these unacceptable provocations and incursions".

The United Nations Mission for the Referendum in Western Sahara (MINURSO) denied these allegations, stating that "no movement of military elements" had been observed in this area.

But Morocco countered those claims on Wednesday evening, presenting the UN with satellite photos showing the progress of construction in Tifariti and Bir Lahlou areas.

Morocco's hidden objective is to change the nature of the Sahrawi question, to transform it from a question of sovereignty over a territory to a question of refugees. And to tell the UN the Polisario Front is an Algerian fiction - Algerian security source

Unlike Al Mahbes, these two towns are not in the buffer zone, which is limited to the five-kilometre belt along the security wall - often referred to as the "sand wall" or the "berm" - that runs practically the length of Western Sahara at varying distances west of its borders with Mauritania and Algeria.

The Polisario Front describes the entire territory east of the wall, which includes Tifariti and Bir Lahlou, as a "liberated area". Morocco describes this territory as a "buffer zone".

The UN does not validate any of these definitions and refers to the Moroccan zone as "west of the Berm," and the Polisario-controlled zone as "east of the Berm".

'A decolonization issue'

The presence of the Polisario Front in Tifariti and Bir Lahlou is not new. In August 1991, shortly before the ceasefire, the Moroccan air force bombed Tifariti as engineering elements of the Polisario Front began construction work. The bombings caused the death of dozens of Sahrawi civilians and soldiers, as well as the loss of two Moroccan fighter jets. The occupation of the area is therefore of great political, historical and emotional value for the Polisario Front.

As for Bir Lahlou, which houses several buildings and structures, it is there that the Polisario Front wants to transfer its presidency.

For several years, Morocco has been indignant from time to time about the occupation of both areas. The more or less unprecedented event - which visibly motivated the Moroccan reaction - was the incursion of the Polisario Front into the UN-monitored buffer zone of Al Mahbes on Thursday 29 March.

Morocco has seized the opportunity to restate its demand that the Polisario Front withdraw from the territory east of the security wall.

Horst Köhler, the UN special envoy to Western Sahara, arrives at Aousserd camp on 18 October 2017 (AFP) The Algerian foreign minister, Abdelkader Messahel, "refused to comment on the Moroccan intention expressed by this ambassador and even considered that it had no value," the diplomatic source told MEE.

"First, because Algeria has a diplomatic relationship with Morocco. It would have been preferable if Morocco had conveyed the message via its ambassador in Algiers, or via the Moroccan foreign minister - not via a third state. Secondly, because Algiers does not consider itself a stakeholder."

For Algiers, the Western Sahara conflict is a "decolonization issue," an Algerian diplomatic source told the APS, the official news agency, while stressing that Algeria has "a duty of solidarity with the Sahrawi people for the exercise of their legitimate rights".

The Algerian authorities "take Morocco's threats very seriously and are studying all possibilities," the Algerian diplomatic source told MEE, including a possible confrontation between the Royal Moroccan Armed Forces (FAR) and the forces of the Polisario Front.

'A dangerous step'

The source refuted Morocco's accusations and described Rabat's verbal escalation as "a dangerous move to undermine the UN's efforts to revive the peace process".

On Monday, Brahim Ghali, the Sahrawi president, declared that the Sahrawi People's Liberation Army (SPLA) was ready "to respond forcefully to any attempt by the Moroccan occupation to undermine the liberated territories or change the status put in place following the ceasefire signed in 1991".

According to an Algerian security source, Morocco is not seeking to start a war, just to change "the rules of engagement".

"Since the ceasefire between Morocco and the Polisario Front, it has been accepted that the Polisario Front is free to move to areas not controlled by Moroccans. And that's what Rabat wants to change", he told MEE.

"Through military intervention, Morocco wants to recover the buffer zone and the liberated areas to say that they no longer exist, and that there's only a Moroccan territory. The aim is to drive the Sahrawi forces out of the liberated areas under the control of the Polisario and impose a new state of affairs," he said.

"Morocco's hidden objective is to change the nature of the Sahrawi question, to transform it from a question of sovereignty over a territory to a question of refugees. And to tell the UN the Polisario Front is an Algerian fiction. Proof: it does not exist on Moroccan territory".

Morocco's refusal to allow the Polisario Front to normalise its presence in these territories, which the Front considers "liberated territories," is explained by the fact that, for the kingdom, this zone is not built as a border between the territory controlled and administered by Morocco and that controlled by the Front.

For Morocco, acceptance of this situation would imply that the Polisario Front has a border, and therefore a territory to the east of the wall.

According to a confidential note from Moroccan diplomacy, leaked in 2014, Morocco believes that behind the occupation of this territory by the Polisario Front "the objective is to move the Polisario from the situation of an armed group in exile to a situation where its territorial establishment would not only be a fait accompli, but also a legally recognized political reality".

Parade of soldiers of the Polisario Front, in 2011, on the occasion of the 35th anniversary of the creation of the Sahrawi Arab Democratic Republic (AFP) The Algerian diplomatic source said he "does not believe at all" there would be direct war between Algeria and Morocco.

"Moroccans are aware that this kind of confrontation could be catastrophic for the stability of the entire region," he said.

For Akram Kharief, founder of the website menadefense.net, the balance of power would be clearly in favour of Algerians.

"Morocco and Algeria have about the same number of men, about 150,000. The Moroccan army is a professional army - unlike the Algerian army, which is an army of conscripts - and on paper is therefore better trained," he told MEE.

"But in practice, Algerians are equipped with tanks, armoured vehicles, guns ... much larger and more modern. Algeria's air forces are also larger and better equipped."

The Stockholm International Peace Research Institute, which analyses arms transfers, highlighted in its 2017 report how Morocco ranks far behind Algeria in terms of military power.

However, the security source did not rule out a military confrontation between Moroccan forces and the Polisario Front, "which could break out at any moment".

"And in this case, we must be clear: Algeria will ensure, through a qualitative supply of armament, such as anti-armour rockets, that a defeat of the Sahrawis is impossible."

A version of this story originally appeared on Middle East Eye's French website.