Within minutes, a barrage of mortar shells flew in the opposite direction, from Moroccan positions, landing with a thick column of smoke in the barren desert of what is known as Africa's last colony.
'Low-intensity hostilities,'' as a recent United Nations report describes them, have raged for the past year along the 2,700-kilometer (1,700-mile) berm a barrier second in length only to the Great Wall of China that separates the part of Western Sahara that Morocco rules from the sliver held by the Polisario Front, which wants the territory to be independent. Both sides claim the area in its entirety.
For nearly 30 years this swath of North African desert about the size of Colorado that sits on vast phosphate deposits, faces rich fishing grounds and is believed to have off-shore oil reserves has existed in limbo, awaiting a referendum that was supposed to let the local Sahrawi people decide their future. Instead, as negotiations over who would be allowed to vote dragged on, Morocco tightened its control of the territory, which was a Spanish colony until 1975.
Last year, the Polisario Front announced that it would no longer abide by the 1991 cease-fire that ended its 16-year guerilla war with Morocco.
The decision was fueled by frustration among younger Sahrawi many of whom were born in refugee camps in Algeria, have never lived in their ancestral homeland, and are tired of waiting for the UN promised referendum.
'Everybody is ready for war,'' said Ahmed, who spent more than half of his 32 years in Cuba before returning to enlist for battle when the truce ended last year.
'We are fed up. The only thing that is going to bring our homeland back to us is this,' Ahmed said pointing at his AK-47 weapon, as he stood on the front line in Mahbas. The region, at the crossroads of Morocco, Mauritania and Algeria, is where most of the exchanges of fire take place.
Ahmed is typical of a generation of Sahrawi youth, most of whom traveled abroad to study from Spain to Libya but returned to the camps to form families. And they've told their elders that they don't want to die in exile, with no future to offer to their own children.
'Life abroad can be tempting,' said Omar Deidih, a baby-faced soldier and cybersecurity student who on a recent visit to the front line organized by the Polisario spoke to foreign reporters in fluent English. 'But the most important thing is that we have fresh blood in this new phase of the struggle.''
The possibility, however remote, that clashes could escalate into a full-out regional war may be the Polisario's only hope of drawing attention to a conflict with few known casualties in a vast but forgotten corner of the desert. Many in the camps feel that efforts to finally settle the status of Western Sahara have languished since Morocco proposed greater autonomy for the territory in 2004.
The front's hopes for independence suffered a major blow last year when the US in the waning days of the Trump administration backed Morocco's claim to the territory, as part of efforts to get Morocco to recognize Israel. Other countries, including the Polisario's main ally Algeria, recognize Western Sahara as independent, while still more support UN efforts for a negotiated solution.
The rising tensions have gotten the attention of the UN, whose Minurso force oversaw the cease-fire and whose secretary-general recently appointed Staffan de Mistura, a seasoned Italian diplomat and former UN envoy for Syria, to take charge of the negotiations.
The Polisario's leader, Brahim Ghali, last week warned that de Mistura must be given a clear mandate from the Security Council to carry out a referendum. Western Sahara will be before the Council on Oct. 28, when members vote on whether to extend the Minurso mission.
Achieving progress is also a matter of legitimacy for the Polisario. After years of internal division, the new hostilities have rallied pro-independence supporters around its leadership, but many fear that the lack of results could lead to more radicalization.
In the camps, the live fire from the front line reverberates strongly among refugees, who were forced to confront the precariousness of their existence when the humanitarian aid they rely on slowed to a trickle during the pandemic.
Medical missions were halted, medicine was in short supply and prices of camel, goat and chicken meat all went up, said 29-year old Dahaba Chej Baha, a refugee in the Boujdour camp. On a recent morning, the mother of a 3-year-old was sheltering in the shade while in her third hour of waiting for an Algerian truck to deliver gas canisters.
'Everything is so difficult here,'' Chej Baha said, adding that those who would typically find ways to work overseas and send money back have become trapped because of pandemic-related travel restrictions. 'I don't like war, but I feel that nothing is going to change without it.'
Meima Ali, another mother, with three kids, said she was against the war, but that her voice was not listened to in a community dominated by men.
'My husband has to decide between finding work or looking like a traitor for not going to the front,' she said. 'How am I going to survive without him? Here, we live as if we were dead.''
Morocco denies that there is an armed conflict raging in what it calls its 'southern provinces,' where about 90,000 Sahrawi people are estimated to live alongside 350,000 Moroccans. Morocco has told the UN mission that its troops only return fire 'in cases of direct threat'' and 'always in proportion to actions'' of the Polisario.
In a response to questions from The Associated Press, the Moroccan government said that there have been 'unilateral attacks'' by the Polisario but no casualties on the Moroccan side.
It called any effort to portray the conflict as something bigger 'propaganda elements intended for the media'' and 'desperate gesticulations to attract attention.''
Intissar Fakir, an expert on the region for the Washington-based Middle East Institute, said that a full-fledged conflict which could pit Morocco and Algeria against each other wasn't in anyone's interest. But she said that negotiating a lasting solution wouldn't be easy either.
'Maybe in terms of international law, the Polisario have their standing, but I think Morocco here is the strongest it has ever been with the U.S. recognition and de facto control over most of the territory,'' she said. But the Polisario, she added, 'is more entrenched in their own position because they really have kind of nothing to lose at this point.''
Although many interviewed by the AP at the camps or on the front line expressed frustration with the years of negotiations that the Polisario defended until last year, open criticism is hard to come by in such a tight community.
Baali Hamudi Nayim, a veteran of the 1970s and 1980s war against Mauritania and Morocco, said he had been against the 1991 cease-fire.
'If it was up to me, the time for a political solution without any guarantees, through the UN or others, is over,'' said Hamudi, who is back in his guerrilla attire to oversee battalions in the restive Mahbas. 'For me, the solution is a military one.''