UNITED NATIONS, Jan. 6 (Xinhua) -- UN Secretary-General Antonio Guterres on Saturday voiced concern over increased tension in the Buffer Strip in Western Sahara and called for restraint.

"The secretary-general 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 Farhan Haq, Guterres' deputy spokesman, in a statement.

"The secretary-General underlines that the withdrawal of Frente Polisario elements from Guerguerat in April 2017, together with the earlier withdrawal of Moroccan elements from the area, was critical to creating an environment conducive to the resumption of dialogue under the auspices of his personal envoy Horst Kohler."

Western Sahara was partitioned between Morocco and Mauritania at the end of Spain's colonial rule in 1976. Morocco has asserted administrative control over the whole territory since 1979, when Mauritania, under pressure from Polisario guerrillas, abandoned all claims to its portion. Fighting broke out between Morocco and the Frente Polisario (Polisario Front), which is fighting for the independence of Western Sahara.

The secretary-general called 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 that may constitute a change to the status quo of the Buffer Strip, said Haq.