The Moroccan military broke into a no-go buffer zone early Friday morning in the non-self-governing territory of Western Sahara and exchanged fire with the Polisario Front, the Sahrawi liberation movement seeking independence. The violence broke a nearly three-decade-old ceasefire brokered by the United Nations in 1991.

For the past three weeks, Sahrawi civilian protesters had blocked a Morocco-built road in the area that Sahrawis consider to be illegal. The peaceful blockade backed up traffic for miles and cut off trade between Morocco and African countries to the south. The Moroccan military entered the buffer zone Friday morning to disperse the civilians, who were evacuated to safety by the Polisario Front.

The Sahrawi refugee camps are under a maximum alert, and the Polisario has declared the return to armed struggle to liberate Western Sahara, which is pending decolonization since 1975, when Morocco invaded the territory as Spain, the former colonial power, withdrew. The ceasefire agreement included a U.N.-sponsored plan for a referendum on self-determination, which Morocco has refused to hold.