UN Secretary-General Antonio Guterres is deeply concerned by a spike in tensions in a buffer zone in disputed Western Sahara, his spokesman said Saturday.

Morocco has accused the Algerian-backed Polisario Front of carrying out incursions in the buffer zone near Guerguerat, an area in southern Western Sahara near the Mauritanian border.

The UN chief "is deeply concerned about recent increased tensions in the vicinity of Guerguerat in the Buffer Strip in southern Western Sahara between the Moroccan berm and the Mauritanian border," said a UN statement.

Guterres "calls on the parties to exercise maximum restraint and to avoid escalating tensions."

"Regular civilian and commercial traffic should not be obstructed and no action should be taken, which may constitute a change to the status quo of the buffer strip," it added.

A previous incursion of the Polisario at Guerguerat last year prompted the United Nations to intervene to force both Morocco and the Polisario to withdraw.