Fresh exchanges of fire in Western Sahara: UN
The MINURSO peace-keeping mission "continues to receive reports of shots being fired during the night at various locations," UN spokesman Stephane Dujarric said.
"We continue to urge the parties to take all necessary steps to defuse tensions."
UN Secretary-General Antonio Guterres spoke to Moroccan King Mohammed VI as well as other parties, Dujarric said.
The king has said in a statement that Morocco was committed to a ceasefire but was "determined to react, with the greatest severity, and in self-defense, against any threat to its security."
The crisis erupted after Morocco launched a military operation Friday to reopen a key highway at the Guerguerat border crossing between the territory and Mauritania.
It accused the Polisario of blocking the highway, which is key to trade with the rest of Africa.
The Algerian-backed Polisario, which does not recognize the existence of the highway, responded by declaring an end to an almost three-decade-old, UN-supervised ceasefire in Western Sahara.