The Western Sahara Campaign, an NGO that supports the independence movement of the local Saharawi people, says Garhi Nayem was killed Sunday as the vehicle he and the others were riding in was nearing a protest camp outside the region’s capital, Laayoune. Those injured were taken to the hospital, the group’s statement said.

A Moroccan official, who declined to give his name in accordance with the rules of his job, corroborated Sunday’s incident.

Morocco has ruled the Western Sahara for decades, fending off local Polisario guerrillas fighting for independence.

The circumstances of the shooting remain murky and it wasn’t immediately clear from either source why the security forces opened fire on the vehicle.

In its statement, the Western Sahara Campaign said the tent encampment was set up more than two weeks ago to protest the “Moroccan occupation and the ongoing discrimination, poverty and human rights abuses against Saharawi citizens.” Morocco has presented the camp, where an estimated several thousand people are living, as a simple protest against poor living conditions in Laayoune.

The Western Sahara Campaign said Moroccan security forces “have surrounded the camp, reacting violently to protesters and preventing supplies of food, water and medicine (from) reaching the camp.” Sunday’s slaying came during a visit to Morocco by the United Nations’ special envoy for Western Sahara, Christopher Ross, who was holding consultations with the parties involved in the decades-long conflict. Morocco’s official MAP news agency said Ross met Monday in Casablanca with the Moroccan king, Mohammed VI, and the country’s foreign minister.

Ross’s consultations have also taken him to neighboring Algeria and Mauritania in recent days, the MAP report said.

Spanish colonizers left the territory in 1975, but a year later they went to war over it. In 1979, Mauritania pulled out and Morocco took over the whole Western Sahara. But fighting continued between the territory’s estimated 15,000 Polisario Front guerrillas and Morocco’s US-equipped army until a 1991 truce.

Morocco has proposed wide-ranging autonomy for Western Sahara, but the Polisario Front insists on a referendum on the territory’s future.

A new round of informal talks between Morocco and the Polisario Front is slated for November. During the last round of informal talks in February, neither side budged and Secretary-General Ban Ki-moon said in April that he saw no prospect of resolving the dispute in the foreseeable future.