Morocco on Wednesday hinted it could act unilaterally if the United Nations and Algeria fail to stop Polisario Front fighters it accuses of carrying out incursions into a buffer zone.

"If the Security Council does not assume its responsibilities, Morocco will assume its own," Foreign Minister Nasser Bourita said after a meeting with U.N. chief Antonio Guterres, as reported by Agence France-Presse (AFP).

He said that Morocco's King Mohammed IV spoke with Guterres directly, expressing "Morocco's clear firm and determined rejection of these provocations, these incursions, by Polisario" into a Western Sahara buffer zone where the U.N. is responsible for supervising a ceasefire.

Morocco wrote to the Security Council on Sunday to report that fighters of the Polisario Front had entered the northeastern Western Sahara town of Mahbes in recent days in violation of a military agreement setting up the buffer zone.

The fighters turned up in "military vehicles, and have set up tents, dug a ditch and built constructions using sandbags," Morocco's U.N. Ambassador Omar Hilale said. Rabat considers Western Sahara an integral part of Morocco and proposes autonomy for the resource-rich territory, but the Polisario Front insists on a U.N. referendum on independence. Morocco and the Polisario fought for control of Western Sahara from 1975 to 1991.