The pro-independence Polisario Front said it launched Thursday "massive attacks" against a Moroccan defensive wall that cuts through the disputed Western Sahara.
The territory is at the centre of a crisis between the two since Morocco last week launched a military operation to reopen a key highway at the Guerguerat border crossing between Western Sahara and Mauritania.
The defence ministry of the Polisario-declared Sahrawi Arab Democratic Republic (SADR) said "massive attacks" targeted several sectors of the 2,700-kilometre (1,700 miles) Moroccan defensive wall.
The wall cuts through the Western Sahara, a former Spanish colony, around three-quarters of which are controlled by Morocco, including its phosphate deposits and lucrative fisheries.
The Polisario controls the rest of the mostly desert region.
The SADR defence ministry said Polisario pounded the sectors of Al Farcia, Amgala and Haouza in the north of the Western Sahara, and Oum Dreygga in the centre causing "important material damage".
There were no further details, and the claim could not be independently verified.
The crisis erupted last week after Morocco accused the Polisario of blocking the highway at the Guerguerat border crossing which is key to trade with the rest of Africa.
The Algerian-backed Polisario, which does not recognise the existence of the highway, responded by declaring the end of an almost three-decade UN-supervised ceasefire in Western Sahara.
Morocco says Western Sahara is an integral part of the kingdom and has offered autonomy for the disputed territory, but insists it will retain sovereignty.