The fragile truce that had lasted since 1991 in Western Sahara has collapsed as the Moroccan military launched an operation in a UN-manned buffer strip in the disputed Guerguerat border zone.

The Moroccan military stated that the operation was launched to clear a key road that had been blocked since October 21, following weeks of “provocations,” by supporters of the pro-independence Polisario Front.

The road cuts across the UN buffer strip towards the border between Western Sahara and Mauritania; it links Morocco to Mauritania. The road is the primary access highway for the movement of goods and people between the two countries.

The Polisario Front considers the road illegal since it says it was built in violation of the 1991 truce.

The Moroccan Ministry of Foreign Affairs had accused the Polisario of carrying out “acts of banditry” and “harassing” UN peacekeeping forces operating in the region.

A spokesman for the Polisario Front accused the Moroccan military of firing at innocent protesters something that led to clashes between Moroccan and Polisario forces on Friday. 

“War has started, the Moroccan side has liquidated the ceasefire,” senior Polisario official Mohamed Salem Ould Salek told the media, calling the Moroccan operation an “aggression.”

Tensions in the region date to 1975 when Morocco annexed Western Sahara, a former Spanish colony that was also briefly occupied by Mauritania. Western Sahara is believed to have rich offshore oil and mineral deposits. For years, the Polisario fought for independence from Morocco in a struggle that lasted until 1991, when the United Nations negotiated an armistice between the two parties.